SO watching porn

Was taking a shower because me and the SO were planning on having fun tonight. We are new parents and my 6wks aren’t up yet and I haven’t been cleared by MD to have sex, but I feel fine. As I got out the showers and cane in to our bedroom he pulled the covers back exposing himself and he was already hard and he replied “I’m just pregaming.” Meaning he was watching porn videos and I felt some way because why would you need to pregame if we are about to have some foreplay and sex which will get him hard already? He thinks that I am wrong for getting mad and tried to flip the situation saying that I’m cheating and just looking for excuses to not have sex with him because I’m having sex with other ppl. Am I wrong for being upset and how would you handle it?