You can’t push anyone to cheat. People are either cheaters or they aren’t. Nothing you can do to push anyone.

Yes you stand up for yourself and speak up. If you’d goal is to build your self esteem up, that’s the first thing people with healthy self esteem do: speak up and stand up and don’t tolerate bad treatment.

Of course if whatever she does with these single men falls into a bothersome category. You aren’t telling us who they are and what she does with them. If they are fellow chess players in a chess club then I suggest you examine why you are upset. If they are people in “adult” chat rooms and conversations are sexual, then yes it’s inappropriate. So again it all depends on what you decided on nature of your marriage. Some people have open marriage or whatever other arrangement

You need to be on the same page