Sometimes women that I have a relationship with tell me how other men treat them with affection, call them nicknames etc.

My first impulse is to just give up. I think: if I tell her that I don't like it, she'll go to him. If I tell her to do it more, I neglect my feelings to her and lie to myself. And maybe she takes it seriously and sees it as me actually endorsing her having sex with him. What can I do anyways about guys that I don't see? Even those that I do see? After all, people do martial arts left and right, have knives and stuff.

The advice that I heard most was "do not fight, only last resort, bad decision". You go to martial arts classes do those exercises just to hear that you shouldn't fight anyways except in this very rare occasion of being allowed to that never happens or when you see it, it's too late.

Probably the only way when she starts saying that is to say to her, next time I meet her: you know, as you got to know this guy better, we continue sleeping with a condom, only, and then just have sex with a condom with her until she wants to see me less and less and finally leave me for him or some other guy.

I mean, what else can I do that doesn't bring me in jail or get me physically hurt?