He's cheating, isn't he? 29M 28F

so, I'm together with this man for 1.5years and 7 months pregnant with his child. a friend of mine saw that he checked out her profile on a dating app. after some investigation i found a girl he was talking to on snapchat, about meeting her, just 2 days ago. now I see some titpics of his ex on his "recently used" on snapchat. he says he got hacked, his files got moved somehow so the pics went up, someone wants to ruin his life and its working. hes using the fact that some random phone logged into his google account (which he showed me and it really did 4 days ago) as an excuse, saying he got hacked and he didnt write with anyone. he even sent google a mail. He also cant login the dating app anymore (he showed me and it doesnt work), he didnt use it, he said. google activity shows he used it frequently for the last 3 months. this is pure gaslighting, right? i told him he can tell me the truth. he said he hid his insta because he wanted to buy a ring to ask me if i wanna marry him. he says he loves me, that i am the love of his life, the most beautiful woman. he doesnt admit it even tho the evidence is clear. but he is cheating, isnt he?