My boyfriend get stage fright (skiddish boner)

So I’ve been dating my boyfriend for around 2-3 months now and I love him and everythings great etc etc. BUT we haven’t had sex yet. We’ve done a ton of foreplay and he’s very adequate in that area so it’s great for me, but whenever I try to insinuate sex he goes soft. I know he is capable of getting a boner and the like because I’ve gotten him off in other ways other than sex. But any time the situation starts to lead towards (penetrative) sex his boner just disappears! It’s pretty frustrating because I always get extremely horny from all the foreplay but I never want to make him feel bad about it because that won’t help the situation. I’ve talked to him quite a bit about it and he just says that he overthinks about it too much and psychs himself out. Basically in his head he’s thinking “I need to be hard now” and overthinks it and gets the opposite effect. I honestly don’t know what to do to help, people please help me!! Tips?? Has anyone else’s experienced a situation like this? If so what did you do to help?