I get that having a harem is part of the fantasy but it kinda bothers me how guys like Regnard can't just say they're in a relationship. Like even if you're not official I do think they're close enough that something is there, and it is something you'd talk to your partner about. If you want to introduce another girl after that finds a reason to be involved then go ahead (ie his skill is too useful, the side effects cause these feelings, you two aren't official, I should be free to do it as well, whatever). It would make him come off as a lot more reliable and considerate of the people around him instead of a mouthbreather who just gets pulled around.