important thing to note: don't get angry, be calm, act as if you've given up, no effort, just shake your head as if you're beginning to realize that she isn't worth the effort anymore.
If she mentions the honest truth that she is planning on meeting another man (highly unlikely but anything is possible), be honest with her, tell her the marriage is over, you're not waiting around anymore and you're going to start looking for other women just to see what the fuss is all about.
She trusts you to be the nice guy/door mat that wouldn't ever attempt to see other women even though your wife is thinking about seeing other men (if not more).
Calm, cool, collected and act as if you don't care anymore.
No more pursuing, no more doing anything special for her.
Do you want to be married to someone who doesn't value you or the relationship they have with you? What kind of marriage is that?
Until you project that kind of self-esteem, self-respect, self-value, no one will ever be able to value you and hold on to you, you just give the impression that you're not worth the effort.