I had the same problem as your husband with condoms. It was difficult to get enough sensation to finish. It took I dunno like a couple hours to finish. In addition to that there could be an issue of dry skin. If he is too dry then he will have reduced sensation as well. A lotion like the cocoa butter ones. Palmers I think. That will revitilize the skin and increase sensation if it is dry.

Another issue may be his masturbation. If he grips himself rather hard and gets used to that, then the vagina can't provide the same amount of pressure. He may want to ease up if he has the G.I. Joe kung do grip going on.

Meds are another thing that can do that. When I was on a couple antidepressant I had an incredibly difficult time to finish. I could, but it took a lot, and my wife said it was sore the other day.

I have taken one medication that seems to have the opposite effect. I take wellbutrin and I find a finish a little faster now than usual. Just a thought, but I don't know about taking an antidepressent just for that. Not sure what it would do to a person that doesn't suffer from depression.