Emotions ruining relationship

Wendy
My SO used to be very patient with me but ever since being pregnant I've been a lot to handle. Eventually his patience ran out and we broke up.... things have been going smoothly for the last month or so. Sleeping over, spending a lot of time together and such. But I got emotional again today and acted on an impulse like I shouldn't have and we pull out the same arguments. Back to square one. He says that he needs to keep me at a distance for me to be nice to him. Is this true? Does anyone else feel like they become really needy and emotional when they're closer to their SO or do they understand why he might feel that way? I'm confused as to why this fight keeps happening.