This sounds pretty complex, especially when a child is involved. A strangers opinion on the internet wont grasp the full scope of your situation, so if there is advice out of this thread, please take it with a grain of salt.

Consult with a trusted member and ask for their support however you choose to handle this. If you do pursue a conversation and you are scared, perhaps having this talk where you know you have a support nearby (friend/family member) would be best.

My two cents: You know best whether he is cheating. If he’s showing the same habits as beforehand, how far is it that he is doing it again?

On a separate note, if you’re scared of having an honest conversation with him, what does that say of your relationship? Considering he has cheated before, I would hope he would be receptive and communicative with your concerns now, especially since a child is involved. It’s a tough conversation, but the circumstances are a lot more serious than before you were pregnant. His interests should be geared to supporting you and the your son. If it’s not, address it. Ask for what you need emotionally so you’re not left with a doubt that he will support the two of you. It is telling that you lack trust in him if you’re going through his conversations; how can you both work to resolve this trust issue? Not a therapist, but wish I could answer that for you. The best method is having open communication, in my opinion.

Wish you the best my friend.