Should I give up or keep fighting??

Hi. I am 22 yrs old, and I have a bf who is 34, still married (but not longer staying with his wife, filing for annulment) and has a kid. So we met each other like 4 yrs ago, and up until now, we are still together. So the thing is, when we became a couple, I was not that serious about him, and I was afraid of being serious because I am afraid to get hurt again, so I'm like testing the waters. So I tested him by texting him as a friend of mine, to see if he is serious about me. I admit that I really messed up and I played with him somehow. So that became a big problem to us. Plus, I have a wandering eye then that's why I had crushes in my office, which became another problem. So he broke up with me then I realized that I do really love him and I can't live without him. So I begged for him to take me back, and he said so many hurting things to me like, if someone comes his way, he will be open for that woman; and that he can't wait for me in 5 years, and he does not love me that much.

So after months of begging and pleading, I decided to give up and focused on my work. I became close with my 2 guy officemates. Both of them admitted that they have a crush on me. Then I realized that I was starting to heal. After 5 months, he came back to me and I told him that I'm already starting to move on. But I do still love him then. We tried to work things out but there were times when he would doubt me.

So last year, 2013, I did everything for him to know how much he means to me. We went out on weekends date, which were so great. And I even helped him one weekend with his laundry, and whenever he is getting mad at me, I would buy him chocolates, coffee, or even write him an apology letter. But recently, he has changed. He was making excuses like he can't meet me after work because he is tired or he has pending jobs. And I waited for 3 hours for him, because I badly wanted to see him. Then one day he would not text me, then he would later on tell me that he was sleeping or doing some household chores because he is alone in his apartment. And last weekend, I received a text telling me that he is already home, when he did not text me where he was going. He said that because he already mentioned it to me yesterday, and because I wake up late during weekends, he did not mention it to me. Another thing is that, I told him that I still remember what he told me before that it is his dream that we become a couple, he said that he can't remember it and all he remembers is that he thought that it is only in his dreams that I will become his gf.

Then there were days when he would not text me, like when he said that he will go home to his son who is with her grandma, and that I can't call or text him because he's son will be reviewing. And I doubted that. I even asked him if he will tell me something, and he said that he has nothing to say. And I asked him why he is distant to me, like avoiding me, then he said because of what happened to us, of me having crushes with my officemates, and he finds it hard to trust me sometimes. Are my efforts not enough to let him know how much he means to me? Then yesterday we had an argument then he dropped down the phone, and I was so hurt because I could never do that to him, even when times get rough.

Pls help me. Should I give up on him since it seems like I can never have him? I am so confused. I am crying every night, thinking why he is doing this things to me now that I am very serious about him. Why did he even get back to me if he has not moved on yet? Why even made me love him again that much? It hurts.. I even made him love letters through blog, while he never gave me any. I even bought him fruits and medicines when he was sick. Is he cheating on me? I'm so confused.. Sometimes he would pick up fights telling me that I blocked him in Facebook when I did not. I just hate arguing with him for no reason. Please help me.. :(((