What Can Be The Cause Of Foul Smell Coming From Buttocks?

My husband is 65 yrs old and he shower more often then I do, His Hygiene is very clean, but,for 21 years - every single night when its bed time, He's bottomless, he says, he gets uncomfortable other wise. For 21 years, I never said anything, I wanted to, but wasn't sure how or how he woud react to such a touchy subject, Plus,I had the hardest approaching with it...But,The past 2-3 years,He has had several foul smells [not all at one time, but one at a time, when one would finally go away[FINALLY!!!!after 6-8months...] another foul smell would come out of his body and every morning when I would get up, I could smell it allover me...''ICK''. But anyway, the past 6 months or so has been beyond gagging for me. We live in a Studio Apt. and when its bed time and his shorts come off, he can go to sleep with no problem....ME?...NO WAY.....He 's sound asleep while I'm feeling sick,after a while, I can smell it in my hair, the whole apt, smells,cant get away,tired of showering 3times a day.So, A month ago, I forced myself to bring it to him, I was very polite about, and asked him to use one of my BUTT-WIPES every night before bedtime. [I would also spray ''baby oil'' all over it. ]He uses it for me. Even after his shower before, I had to make him get up to use a butt-wipe. [ EVEN HALF THE TIMES THE BUTT- WIPES DONT WORK, MY WIPES WERENT SCENTED, SO, HE WENT OUT AND BOUGHT SOME THAT WERE SCENTED, NOT ALOT ODIFFERENCE. I didn't mean to write you a book, I've just never told anyone before. Can you tell me what's going on?