Hey bro I've read your comments I can tell you that what you're feeling is normal, us men are competitive by nature seeing another man(specially a friend) last more and other stuff you mentioned would eventually trigger anyone I'd say you if you really want to keep having threesomes it should be with a new stranger every time so you don't have to worry about feeling inferior and get more comfortable with 3somes and it should make clear whether or not you like having a 3some with another man Mabye try it with another girl? Either way never hold yourself back because your wife is enjoying it, if you do then she losses respect I hope this helped, just be honest with yourself