martinr:
The wife should be in charge of that decision at all times.
I agree. Although my wife and I originally decided on a couple of ground rules, one that she wouldn't go with anyone I knew and two, that she'd make the guy wear a condom, neither rule lasted very long at all. I accepted that it was her pussy so it was up to her who she fucked and how. Although we used to have sex before and after she'd been with another guy, this eventually dwindled so that in our last year together we didn't do it at all. My wife however was getting fucked on a regular basis and I had no problem with that.
Peter C