How do you single moms do it?

Me and my fiancé had our son 8 months ago and our relationship has just gone downhill since his birth. We constantly fight and disrespect each other and intimacy is non existent. I don’t want to fall out of love with him but I’m afraid the love is gone from our relationship and it’s probably best we go our separate ways. I’m just scared because I’m a stay at home mom and we just got a new apartment together so we’ll still be living together for another year and I can’t afford to move out. How do you single moms move on from a breakup with your babies father when he’s so involved in his sons life? I’ll be seeing him everyday and I think it’ll kill me when he starts dating but i know once I move on I’ll be happier. Any advice?