Have you ever had trouble getting hard during penetration? If so, what could be causing it?

I finally went to a hotel yesterday with a man who offered to meet me, after we’d continued seeing each other for eight dinner-only dates (allowance: 30,000 yen). The allowance this time was 150,000 yen. After we’d been having sex in the missionary position for a while, he suddenly shouted, “Ahh! I can’t get hard!” We tried various positions, and after a while he was able to finish without any problems. But I’m wondering whether it was because my body or tightness wasn’t quite right, or because he was nervous. By the way, afterward he asked when we could meet again. I thought maybe this was just a trial period, and that next time would be when we figured out whether we were truly compatible or not. Still, I’m a little worried that he might cut things off after the next meeting. I do have other sources of income, so it wouldn’t be a big deal, but he was easy to talk to, had a respectable social standing, and was unusually decent for someone from a dating club, so I’d still feel a little sad. Dating clubs are much like life itself: people meet, then eventually part ways. Here I go asking another fairly sensible question.