34 weeks pregnant and me and fiancé keep arguing!

So I am 34 weeks pregnant. Me and my fiancé keep arguing over so many petty things. First over his children I got upset that they don’t listen to me so he ended up sleeping on the sofa. (Not my choice) Then he made a comment about his ex making him tea because I wouldn’t. Then other petty things. Then it started to get a little more serious. I found history on his phone of him watching porn while I am sat downstairs in the house. Some people won’t care about prom but I do and always have done and he knows that. I have so many insecurities and hate myself and that’s what hurts knowing he watches that to get off to. Well we sorted that out, then a few days later I receive a message saying word is that he is cheating on me. I generally don’t think he is and I trust him but so much is. Is going through my head. Am I enough? Am I what he wants? We are meant to be getting married in August as-well as having a baby in January. My head is all over the place.