Confused!!!

I don’t feel the same anymore. I hope this makes sense. I don’t feel anything for my boyfriend and father of my child anymore. We started dating in 2013 and moved in together a year later. The baby is only 4 months old. I think I have a lot of resentment about how disrespectful he hasn’t been to me. I don’t show affection anymore and when he tries “to give me affection ”I feel uncomfortable. I’m afraid to leave. What if this is something temporary? We both planned having the baby and we love and care for him so much but my feelings started changing months ago and no I don’t like anybody else. I was not being treated right. I don’t want to go into details because it would be too long. As far as I know he hasn’t cheated on me even though I’ve found inappropriate messages he sent other women’s on Instagram. His disrespect has been more verbal than anything.

I have express my feeling towards him being so disrespectful but nothing changes.