Porn in car

I’m 30 weeks pregnant but have tried to maintain an active sex live with my guy... and I don’t get it as much as I would like. Maybe once a week. Before we started having sex years ago, he did have issues keeping It up, but I was patient, never made him feel any type of way.. and I think it’s gotten better.. here’s the thing, I always have to be on top. Because if there’s any slight movements from him, he goes soft... again I’ve been patient, I’ve brought up , maybe going to doctor.. but he doesn’t want too.. come to find out, since I’ve moved in with him.. he has started watching porn in his car. He says he doesn’t masturbate in car but he is priming in himself.. whateva that means... any advice you guys can give me.. he also says I’ve been stressing him out and that’s a major turn off for him