Real love? Or just rebound girlfriend?

Hello! I'd be really grateful if someone could help me with this but nevertheless I'll feel better letting my feelings out in the open. This is very, very long, so thank you in advance to those who read it to the end.

I met this guy on August at the school I'm currently enrolled in. Since I'm kind of shy, and it was the beginning of the first semester, I didn't talk to him, instead making some new friends on the side. Two times, me, him and some other classmates went to the movies but he and I didn't really talk beyond simple questions about work, school, movies, etc. After almost a month, he started talking to me. We were studying animation, and I could really tell he has a passion for the subject (he even works as an animator at a studio) and vice versa. We immediately hit it off as friends, talking amicably about random subjects.
Not before long he asked me to go out with just him, later telling me that he had arranged for me to go to the movies because he was going in the first place. We went out on two dates. On the first one, he made his intentions towards me extremely clear: he liked me, a lot, "felt a connection" to me and wanted to continue to go out with me. Thing is, he had a girlfriend, who he had dated for 2 years and was going to marry, but since they had been falling out for a while now and the love had kind of, according to him, fizzled out, he was going to break up with her anyway. I immediately told him how bad I felt about that but he reassured me he wanted to move on from that relationship. So I agreed to go out with him. On the second date he told me he was single already, asking me if I wanted to be his girlfriend. I said yes. We kissed on this second date. I won't lie, I felt a very strong connection to him too that I hadn't felt with any of my last and only 2 relationships.

For the next 3 months everything went fine, extremely so, even. We got along really great, I had already been introduced to his family as his girlfriend, and they loved me almost as immediately. He told me his ex-girlfriend wasn't well liked by them in the 2 years they dated; he had even had an argument with his dad which had come to blows over the fact that they were going to get married. We had sex for the first time a week later. This was something strange, maybe. Since the start we had talked maybe jokingly about that. We really, truly, felt a connection between us beyond the physical (at least on my part; I'll concede he's not a very good looking guy, though he told me he was extremely attracted to me). He told me he hadn't had sex with his girlfriend at all in the time they dated, since she is very conservative and wanted to wait until they were married. I was a virgin and wasn't planning on having sex at all until I met the right person, no matter how long that took.
We fell in love, we truly did. He really is the most caring, gentle, honest guy I have ever met and I feel extremely grateful everyday for having met him. He told me "I love you" every single day and would go to great lengths to demonstrate it.
Problem is, I think we took things extremely fast. Not two months later he was already telling me things like how he wanted to get married and have a baby. He's amazing with kids so thinking of him as a father didn't bother me at all. So some days we talked about the fact of moving together and having kids, about our possible future together. I saw it as a distant future so our talks weren't completely serious to me, even though I constantly told him how delighted I'd be to be his wife.
Here is where things started to take a turn for the weird. The school we went to isn't very good, and since he was already working as an animator he told me he was sick of wasting his time there. So he dropped out. Generally I could tell he had other serious issues in his life as well: his mother had died a year ago and he hadn't had the proper chance or courage to grieve her. After a while he told me he wanted to change schools to another state, to the school he was going to previously but had dropped out of, but the thing is, he wanted me to go with him. I was confused and couldn't give him a straight answer for weeks, while he kept softly but firmly encouraging me to go with him and "find our place in the world". Things stayed that way when, one day (and here's where the ex comes in), a close male friend of his who is also my not-so-close friend, sensing my confusion, told me to "let him go". The reason, according to him, was that he was still going out with his ex (he had met her on one of his "errands").

That day I confronted him to tell me the truth and made somewhat of a scene. I had no reason not to trust him. Again, he's extremely open about most things and values honesty. He was in good terms with her (she was the one who still contacted him, from what I knew) and I knew that and supported him on nurturing good vibes between them. But then I found out that at least 2 times he had done random errands for her, because she asked him. That day he was going to take a school paper to her house but he hadn't told me about it. After that, from the scene I made (I even slapped him, hard), he told me he was moving abroad alone and that he didn't want a relationship with me anymore. Hours later, he called me, apologized and changed his mind about breaking up with me, asking me again to move out with him.

Apparently, he is a very unstable person-- he decided he didn't want to move out after all and wanted to stay here, with what was left of his family. I've always told him I'll support him in whatever he needs, as long as he does the same for me on our path in our relationship, and that I probably would've moved out with him since I had nothing to lose (it was a very good school we were going to). So for a while things stayed the same as before, but we had some serious talks and some arguments.
I cry very easily, and he absolutely hates to see me upset. So he decided to have a break and stay friends until he could sort out his problems and be ready for me, because he knew this was hurting me. Amidst this whole issue, there was a very real possibility that I was pregnant.

This is where I stand with him now. We are close friends. I know he talks to his ex still. She asks him to do things for her still and even tried to kiss him once. He refused and got angry at her and made it clear they were just friends. She brought him a Christmas present and he's going to buy her one too (he really, really likes spending money on the people close to him, though). One day I asked him if I could go out, as friends with a guy I know, asking him also just how much time he would need to sort out his feelings, just so I could know he wouldn't leave me hanging by a thread for a long while. A week later, having found out I wasn't pregnant after all, we go out as friends again but he's extremely touchy-feely with me, to the point where he's doing practically everything but kissing me. He told me he felt hurt and a little angry that I wanted to go out with a guy just to "take my mind off him", to the point that he went out with his ex two more times (with his close guy friend as well). He then told me he was disappointed I wasn't pregnant, because he would be very happy to have a kid with me.
Right now, I don't know what to do. We're friends, but he treats me like his friend with benefits. He says he wants to have a baby with me, along with everything that entails. I know it wasn't a break-up; he said he just needed some time. But is a week enough? Should I be worried about the ex-girlfriend that he says he misses sometimes, but who, according to him is like his little sister now? She is still not over him and has asked him to come back.

He wants to have kids with me again, but he is neither in a relationship with her nor with me. We both know we could have an amazing future together since our goals are pretty similar (his and his ex’s weren’t), our pasts have been alike in some ways, and there is just this really strong connection between us we can't deny. Am I being paranoid and need to be more patient? We are really good friends. From the time we met, our conversations have been mostly philosophical and intellectual. He knows how to make me laugh. I’ve also taught him English in exchange of him teaching me animation. I wish we could take things a lot slower, and also, more than anything I wish he could tell his ex to leave him alone, since he hasn't told her he's met someone else he's supposedly in love with (he told me he doesn't want to hurt her, but aren't my feelings more important than hers?) I wish I could meet her and somehow tell her, politely, to back off. Am I being used? I want to talk to him about this but I don't know where to start.

All this angst in only five months? And talk of marriage and babies!! You'd be crazy to continue with him. Too many red flags. And I hope you've now got some contraception sorted out - you don't need an unplanned baby in this mess.

Lastly, get some anger management counselling. That slap on the face you gave him is called assault. I honestly don't know why some women think its OK to slap a man. (If you believed it was wrong, you wouldn't have done it)