Should I Stay Or Go????

Ive been going thru it with my man while he's been locked up...When he got locked up everything that he was doing seemed to come out. This girl he was "talking" to was posting stuff on fb about how she missed him, and it has caused argument after argument! He broke up with me because he felt that i dont believe him, but how could i when he had given me reason not to believe him. It makes no sense. We argue because of what hes doing and he makes it seem like im the reason why were in this predicament. I even spoke to one of his close friends about it and he told me,"oh, I'm gonna be at your wedding one day" , but i feel like he's just saying that because thats his good friend and he wants me to continue looking out for his homeboy. My issue is that i dont know whether to stay or leave!! i love him a whole lot, but he isnt giving me what i want, and that is to be with him. Not to mention the fact that he cant do absolutely nothing for me behind bars, and at the end of the day...Im the one taking care of him...Idk what to do anymore. I feel like as a good person you dont want to kick someone while they are down, but how is it that i feel like he isnt there for me the way i am for him. I Just feel like if things are like this while he is in jail, then i can only imagine what it would be like when he comes home. I hope that he changes and realizes,but at some point i have to be realistic.....Who's to say he will change and/or realize. Oh! And P.s. I live with his family by the way, and it makes it sooo much harder.. his family thinks that him and i r together, and we become closer everyday....