I dont know what to do

Sorry for the long vent post. I'm at a point where i'm second guessing my relationship with my boyfriend, the father of my kids. We've been together for 3 years. He's 29 and I'm 22, so it's a big age gap for me. We're at a point in the relationship where we don't really respect eachother anymore..? Atleast on my end, that's what i feel. We call each other outside of our name, are bickering a lot more, get more annoyed with each other. I have been thinking about ending our relationship for the past 3 weeks which isnt normal for me. Not only do i feel alone, i'm lonely. Even in his presence and company. I feel a part of the walls of our house when i'm with him. I constantly have tried to keep our relationship going. I tell him my wants and needs. I ask him to be more affectionate, and tell him what he should do to make me still feel loved. I dont think its wrong to do that, i mean atleast i'm still kind of trying in other ways than that. I try to talk about our relationship and ask him what we need to work on or what he feels about us, and he gets offended when i do ask those things. He tells me if i want to leave, then to leave. Even when he playfully says it sometimes, he puts no effort in trying to improve. I feel like hes so comfortable that he has stopped trying. I find myself looking at myself to see what i need to improve on to get him to like me if that makes sense.. which is ridiculous. What kind of relationship is it if i have to beg for his attention?.. it makes me sad that i feel this way because i love him so much. But i feel like i am worth nothing to him anymore. I'm not going to act like the good guy though. To be honest, sometime i push it. When he isnt nice, i tell him thats probably the reason why hes been divorced. I found his ex wifes twitter (shes 25 now, divorced for about 4 years) and she retweeted something about how people get comfortable in relationships and how sometimes people don't know the full impqct of their words. She retweeted it saying how that lead to a divorce and how she felt lonely. He always blamed the divorce on her and his family calls her a bitch and what not. But i knew there was more to it, and it makes me sad that she felt how i feel. Even though it was one tweet and i dont know the full story it makes me sad that he has not changed and how he still says shitty things that hurt. He was a dick to her as he is to me. I dont know, i'm just venting but honestly i'm hanging by a thread here and he doesnt know it and neither does his family or mine. He is completely oblivious about my feelings and where im at mentally, but when i do bring it up to try to get us to a better point, he shoots it down and gets defensive and offended by all i say. I'm so tired of seeing his face but yet so sad because i know i deserve a much greater love where i dont have to ask to be appreciated. I want it to be him but right now, it isnt.