very long but I would appreciate if you would read

So I'm 21 and I started dating this guy and we have been dating for a while a little bit into the relationship he told me he was bi which I was fine with I wasn't worried because he seemed so into me later on down the road I find out that he cheated on me with a guy and when I approached him about it he said he was sorry and that this always happened after a few months of dating a girl he would fall for a guy so I told him it was okay and that maybe he's just gay and he should try dating a guy although it broke my heart I wanted him happy. This hurt me the most because he was the first guy I had sex with, I told myself I would never have sex because I've been physically abuses in the past by a member in my family but when I met this guy he changed things so when this all went down you can imagine what went through my head anyways we started dating about two weeks later after I spent the night at his house and had this long talk he said that he knew what he missed I told him it would take a while to trust him again.. Things have been absolutely great he has had a crush on this coworker at work and it made me worried and things have just changed lately and he said it was happening again so I decided it would be best if we broke up. This is hard not only because he was my first after having such a big thing happen to me, but because we basically lived together for like 7 months, and I don't talk to my family so his family took me in and treated me as their own and for the first time it was like I actually had a family that actually loved me. 

I'm having such a hard time.. Any body been through similar situations one any positive feedback would be great?