I think my marriage is falling apart

Hi guy's my husband and I have been together for 10 years and married for 4 of those 10 we met wen I was 14 and been together ever sense we just had a baby 3 months ago a beutyfull baby boy but honestly I feel like that's the only reason we're still together we haven't been intimate sence I was about 5 months pregnant we only had sex once because I brought up the topic but one's in 8 months doesn't seem normal I believe that he is cheating on me because honestly no man goes without sex for that long specially because we used to be berry active I have talked to him about it the best way possible without accusing him just telling him that if he no longer finds me attractive or loves me it's ok that I understand but that maybe it would be better for us to separate and that even if we're not together he will always be able to see his son and spend as much time as he wants with our child but at the end I always end up feeling horrible like I'm the one that's wrong I don't know what to do anymore I do love him but at the same time the more time that passes I start to resent him more I don't know what to do anymore I want to be happy but I can't be happy in a loveless marriage I don't know what to do or how to talk to him anymore please help