I can't imagine sharing a woman with other men. It's just out of the question for me, even if the other guy is less attractive etc. In other words, I couldn't offer any "reciprocity" to my girl if we decided to bring in other girls.
Idunno. To be fair, never in my life I've seen anything particulary wrong with my girl having sex with other guys, but then my ex got into my head and somehow turned it all around. For whatever reason, I've shaped my opinions far too much in her image and can't quite get rid of it ever since.
Doesn't change the fact that while I wouldn't got for threesome with a guy because... Well... Ew, I'm far from being the jealous kind, and I'm unhealthily tolerant on top of that. I do think I have the traits to make it work, I just need to get rid of the superstitions I've picked up for whatever reason - because, objectively, I just can't see anything wrong with it.
I do very much trust my wife, and even if I told her 'hey, go have sex with another guy' and then called her a minute before that to call it off because I'd be feeling bad about it, I'm very certain she'd just turn around and get back to me. Because she's like that. Far too loyal to people she loves.
I was also going to suggest the inclusion of another woman but then I thought that she probably aren't into other women, but it seems like not even that does stop her :) I have another suggestion! This one is just for fun. If you ever go on a vacation together, somewhere far away where nobody recognizes you there are these kind of remote-controlled vibrators that you could buy. I have never tried this myself but I think that going on a sightseeing together where you do make a frequent use of the remote would be great fun.
*Makes note of it*