What to do about my boyfriend?

cont..they used to work together that is where they met, each of them were in a relationship and she told him about his gf at the time cheating on him. they became good friends, well recently of course she lost her bf. she is using him as a rebound, if she was a true friend with him then she wouldn't have done this, friends respect other friends relationships not try to become that other person no matter who it hurts. what also makes me upset is that when he lived with meand he would go to his parents house for the day, being as happy and loving as you can get and then for some reason he would always come back doubting us, it was and is neverending, all i want is for them to like me, im not a bad person, but they think so because i have 2 kids. we have been together 2 yrs and ive seen parents like 5 times, i try to know them but they dont want it. I love him so much, past relationships have hurt me, i really thought he is the one, i dont want to lose him, keep promises, love matter