Should i stay or should i leave????? Is there any HOPE??

ok ive been with this girl for 7 years now. Over the years we've had our differences, but have always stuck together. At one point in our relationship we seperated and hardly talked for around 6 months. During that 6months i met somone else, and had a strong, very intimate relationship with them. I ended up getting back with my ex, and things seemed a whole lot better. We got along better, she seemed nicer, everything was peachy clean. Now, a year later, i'm having major issues. I still think of that girl whom i spent those 6 months with. Actually about everyday. Another thing, she had found out about me being with that girl and ever since she claims she dont trust me because she never thought i would sexually be with someone else and always thought we would always be together. And here is one of my biggest problems right now. Its kissing, and being romantic. Everytime i'm with her, it seems like it's getting harder & harder for me to be romantic towards her, as well as kiss her. I mean of course i kiss her, but i'm talking about a "long, passionate kiss". She tries to give me those, but i feel nothing! Its like my desires have shifted. I no longer really look forward into having sex with her like i used to. And when we do have sex, its more less we go straight into it, without any foreplay. Today she even told me that she wishes i would try to get her in the mood, rather than us just jumping straight into it. But i find it hard to do for some reason. I dont know why. She doesn't have many friends, and we've been together for so long i feel like i'm all she's got. I feel like if i leave her for good, then she will have nobody, and be depressed and upset all the time just like during those 6 months we seperated. I really don't know what to do. I'm so confused. She wants to get married. She told me today that we cannot date forever, that she wants to start a family soon. She also said after being together 7 years, she deserves some kind of commitment which i already told her i couldn't give her right now. That makes her angry, but its SO hard to give a commitment, when i'm not 110% sure. I really don't have many people to talk to about this, which is why i came on here hoping for some help & advice. I do love and care for her very much. And i know deep in my heart she loves me so much, and would do anything for me. I know that. But is it possible to really love somebody, but not be "in love" with them? I would like this to work. I think we make a good team. But the sexual desires, romantic ideas, all of that is disapearing slowly but surely. She gets mad at me because i can't look her in her eyes when we kiss. She claims when we argue, i could give a shit about the problem and could careless about resolving it (which most of the time is true). Another thing, the thought of her being with some other man & taking my place is another thing that gets to me. Just the thought if i knew that would proabbaly be enough to make me want her back regardless of how our relationship is. Anytime you've been with someone for 7years, you feel like they're yours. But then i sit and look at the good points and those are what keeps me from saying screw it. Like for instance, we both love doing the same things. We both like to travel, we like about the same type of food, same places to eat, all that stuff. Even our taste in fashion is about the same. (brand name wise). Also she's a nurse and then i look at if we got married, how awesome our benefits would be, being she works at the hospital. Oh and by the way, she never found out about me and that girl having sex. She only knew we were in a close relationship with each other, knew a lot of things except i never could tell her we had sex. See, she was the only girl i had ever been with until i met this other girl when we seperated. And she asks me all the time, "so you promise me i'm STILL the only one you've ever been with" and of course i have to say yes because if i said no it would absolutely kill her. could me being with that other girl romantically, & sexually have anything to do with the way my feelings and emotions are towards her? Is this something i can overcome, or will go away? What should i do? is it normal that i continue to think of that other girl a lot? Should i break it off, or try to work this 7year relationship out? What are a few options? Thank you for whoever sat here and read all of this, and that will provide me with any suggestions. I greatly appreciate it

Alright, I can't say that I have been in the same experience as you b/c I've never been with anyone for that long. But I have been in a relationship that lasted 2 years and the same thing happened to me. I lost the feelings I had for him when I first started dating him but I still loved him. So yes I do think you can love someone but not be "in love" with them. From reading your story, I think that maybe you guys would be better off if you stayed friends. I think maybe you need to go out and date a few more people before you decide if she is "the one". B/c if you are still thinking about that girl you were with for 6 months then obviously you are not ready to commit with your g/f. The longer you stay with her, the more hurt she will get. I'm a firm believer of "what is meant to be will be", so I believe that if you guys are meant to be together, you will be. Go out and have a good time, meet some other girls. If she is right for you, you'll be together in the end. Thats what I did with my ex of two years, I left him and dated some other guys. He was a mess, just like you are worried about with your g/f, but he got over it. It just takes time. But now I am happier then ever, and I'm glad I thought about myself and made myself happy. If you need to talk feel free to message me, I'm willing to listen. Good luck!!