I don’t know if my boyfriend is cheating on me

So I’m 7 weeks pregnant and we’ve literally been trying for months.

I saw on social media he was at this girls house with his friends (I don’t like this girl nor do I want him around her and he knows that)

She’s constantly posting pics of them and when i confront him he tells me exactly what I pretty much want to hear but I don’t know if it’s true.

as far as I’m aware he has never physically cheated on me, but he won’t stop hanging out with this girl through his friend group.

He doesn’t text or communicate with her but she is always posting pics of them, and he never tells me when hes there I just find out through stalking her -.-

He tells me he doesn’t wanna stress me cause the baby and everything and he’s only there cause his boy likes this girl but idk I just don’t know

Suggestions ?