I'm in desperate need of relationship advice...?

I have been in a relationship for over two years with a man that was my superior officer in a law enforcement setting. We now have twin boys 1 yr old. Here is a brief history...we started off great! Loved spending time with each other and were on the same page majority of the time. Then I noticed he would fly off the handle and break up with me over small petty things. Then a few days later everything would be fine again. I couldn't wrap my head around the reasons behind this behavior. I became pregnant and we decided to have the children, we planned on getting married (he even spoke to my father about it) two days after he moved into my home I found out he had been cheating the entire time we were together. I found videos of threesums and foursomes he had text messages, pics sent back and forth, emails, personal ads, and with SEVERAL different women. I kicked him out. He apologized and vowed to never do those things again. He blamed it on stress. Again I caught him an again and again. It was outrageous behavior. We worked through it and I took him back. He left to go overseas for a much better paying job. I left my job as a cop to stay home with my children while he supported us. Now, on bad days, I get a guilt trip for staying home and being supported by a man that makes 200k now. Mind you this was his idea. We broke up AGAIN for a while on my terms because of all the crap I had been put through and now have decided to try again. Marriage is on the agenda and against my better judgement. What do I do? He keeps this behavior of breaking up with me when he feels like it. He gets upset at the most petty stuff for example (I posted a pic of a fallen officer and I was cause for a break up...I get blamed for everything even when it is not my fault. And I have no problem admiring when I am wrong. He also treats me as a subordinate and not an equal and I feel disrepected. For example he posted pics of himself on facebook with his shirt off. I told him I felt disrepected due to the fact that women we used to work with can see those photos. Mind you he cheateD on me with some women on the department. At first he said he didn't mean to upload them. Really? U didn't mean to? And then he tells me it was for workout pics (he is a body builder-speaks a lot). What do I do. I need some advice. I'm weary and tired of trying to hold us together. An I feel like I walk on egg shells on what I can do and say. My opinion never gets heard by him and any loving critcism i give incorporates a break up ..."go find another nab that will make u happy", "you need to rethink our future" etc...HELP!!!!!