Ex boyfriend

Boyfriend left me at 3 months pregnant because of his mental health. Been going through a lot with work, school, family etc I am so hurt we been together for 8 years he tells me all the time to just focus on myself and the baby back in March I felt something was wrong he began to distant himself from me however never cut of any of his friends am so afraid it’s really because of someone else although he tells me it’s not I never found anything he still pays all my bills so i don’t know what to think or feel he even stills stays in the home we bought together if it was someone else u would think she would wanna come over or why isn’t she allowed to come to his home i feel like it’s his mental health because he did make the comment am going through depression right now n the other half of me feels like he’s having sec with someone there was multiple times I found semen on his boxers when washing clothes but he could be getting one off himself. He is super cautious bot everything so I don’t think he would have intercourse without condoms. Am so upset n hurt I am moving out soon to give him space before the baby gets here there is so many unanswered questions but he refuses to talk to me n shut down