Ex boyfriend or new??

I had been with my boyfriend for almost a year, he treated me like a princess, we went through a lot together in the short time, he supported me through so much and i would have died without him, he was my rock. Towards the end physical attraction was more than lacking and we hardly ever had but we spent all our time together. He recently broke up with me pretty much out of the blue as we didn't really argue and he hadnt really said anything about seriously breaking up. He said it was because i didnt respect him. I was heartbroken I thought it was all my fault although i loved and stil do love him soooo much deep down i knew I wasnt giving him or couldnt give him everything a girlfriend should, i wanted to so I begged for him back and he did very briefly until breaking up with me again. I accepted it was over. Shortly (probably too shortly) after I met a new guy, I am really attracted to him and I know he is a really nice guy and he likes me too, there is so much more physical attraction, but i dont know if thats just because he is new. Anyway my ex cam and asked for me back...he said he would me more relaxed everything wud be on my terms and he was really sorry! I feel so awful because he has nothing to be sorry about really he was soo good to me and i really want to make him happy, i miss him but i know it wasnt a perfect relationship. I think if I wasnt with this new guy i would go back but i dont know what to do i feel like i am having an affair, although im not, it cud just be a fling and if i dont wont to lose what used to be and maybe cud be agin real love...soooo confused, please help! sorry its so long!