This makes me wonder. If in any of these games, a companion outright cheats on the PC and we can actually see the two together, I can't help but feel that people would blow up these forums about whether or not we should be able to either kill the cheater, or the person the companion is cheating with. Needless to say it wouldn't be pretty.
You don't say...
It doesn't have to be a BioWare games, and if it's happen in any game. Well, from my experience, most people don't enjoy being cheated, and if we actually see the two together, but cannot take action, say and do anything about it, or confront the cheater or the person the companion is cheating with. In this kind of situation player's agency shouldn't be taken away, especially since it's a BioWare RPG where your choice shape and drive the experience. I suppose it'll be the best if there are many different approach to the situation. Yeah, I can already see the rage in the BSN (especially if you cannot do anything in the situation). You're right, it wouldn't be pretty at all.
I rather not want BioWare to take this "your love interest is cheating you" idea at all if they're going to take the player's agency and choice away, and not to mention it's weird and shitty if everyone has tendency to cheat on you.