He can't cum

Our sex life has always been great and there have been some times where he's had "whisky" dick and what not and hasn't been able to cum. We have been TTC since October of last year. Once again, our sex life is great, but unfortunately with out schedules it's not often. He works nights during the week I work days and every other weekend we have our kids. Well, this last month he got hurt at work (he's a police officer) and AF came right after that. So it's been a few weeks since we've had sex. Last night we had sex and try all of our normal positions that would typically get him off, but nothing... This has happened the last 4-5 times we've had sex. He takes testosterone and has for a while, he's in shape, he's stays hard during sex... He's just not able to cum. And I'm trying my best to comfort him... Because he feels terrible about it considering we are TTC. Does anyone else's husband have this problem. I told him we would quit focusing on TTC and just get his issue resolved and then we would try again then... Do you know how hard that is as a women that REALLLLY wants to be pregnant?!?