Tell your buddy to chill out. Women keep alot of crap about their past quiet because they assume a guy doesn't want to hear that....And they are 100% right. The same way I don't tell my wife about this one and that one, she keeps shut.
Guys love to have a super star wife in bed, but act like like teenagers when the realize ANOTHER guy invested time in teaching her that thing that she does.
I agree, not smooth on her part for telling him that, but now, your buddy needs to man up and let it go. If there is alot of other crap going on between them, get a divorce, ruin your marriage, mary a virgin, whatever. He needs to just say this sucks (no pun intended), and move on.
Hating on the other guy for getting blown by your wife is pretty stupid. He was just being a dude, and it was a long time ago.
For the record, alot of men who claim to be really big on "respect", in actuality have a lot of problems with their own insecurities.
I'm gonna go now and teach my wife something new.....
Ride like you pay a mortgage...