SERIOUSLY CONSIDERING LEAVING!

I have been with my SO for almost 2 years now. I have been faithful to him the entire time, but I did catch him talking to 3 other females. He constantly questions me about what other guys I'm dating or associating with. I am 8 months pregnant so I'm pretty sure no guys would even want me at this point. I don't even have the desire to cheat. I rarely go anywhere other than home or work anyway. Last year, he decided to go to my Facebook account and read ALL of my messages. He had the nerve to get mad about something I was discussing with my ex 6 years ago. He has been judging me for it and causing unnecessary drama. With him, it's always something. I'm just sick of the drama and feeling like I have to reassure him of my loyalty every month or whenever he gets in his insecure zone.