My boyfriend lost his bonner during sex

Shortly after meeting my boyfriend (26), he lost his bonner during sex and that traumatized him.

We currently have a distance relationship so the recovery of this issue has been slow (about 6 months).

This week I came to visit him and the problem seems to have disappeared until yesterday when we were having sex his dick was going down gradually. He told me he thought it indirectly and then it happened.

Then we were talking about this and he ask me what to do but this has never happened to me before.

In my opinion I think he thinks that he doesn't satisfy me sexually (because I have a high libido) and that's not true, he satisfy me in many levels and I really love him, I don't want to be distanced for this.

What do you think I should tell him?