Smelly and lost ! Hmm...?

I'm young (29) and my fiance is young, as well (22). We are engaged, have a daughter, live together, etc. For the last couple of months, fiance has not been interested in . The last time that we did have ; it just did not seem right. I've been practically begging for the last two weeks. So, one night, we're in bed and I'm asking him if he's just not ually attracted to me anymore and he says, "Well, remember that time when my went limp? It wasn't because of the position (he told me that it was the position and that he couldn't feel anything), but it was in fact because of an odor. Of course, I'm horrified, but I ask more questions b/c I've never smelled an odor and being a NURSE, I think that I would know what different odors smell like and mean. Anyhow, he then goes on to tell me that it has happened two or three more times (the odor). My dilemma is: I feel that he is lying. If I have morning breath; he'll tell me. If I need to go wax my upper lip; he'll tell me to go shave my "mustache" off... he has no problem being upfront with me; as I have no problem doing the same for him. He said that the smell wasn't fishy; just smelled like sweat! Does a male lose an off of sweat?! Someone please give me some insight. I take regular showers, so before I say he's cheating... I'll wait for some answers. Mucho gracious!