Feeling worthless because of a man's opinion

OK... I have searched high and low to help my friend. A real friend... I promise.

She became interested in a guy who showed interest as well. They became close. She knew he had a gf but learned that they lived together. He lives overseas and met him in person on a long stay in the states. When he got back home he checked out for a bit (assuming guilt even though they never got sexual). She still talks to him and still flirts and loves when she does but (he travels a lot) whenever he's home she goes into a massive depression.

Her main hitch is that she feels worthless. She sees their relationship and his "rejection" of her as proof (in her mind) that his opinion of her is that she is worthless and "less than" his gf. In her words... how can I be important at all when he has everything he needs... the love of his life who he can't wait to be with? It has been 2 years and she is caught in a cycle of feeling "not good enough" and "worthless".

I've tried to sell her on therapy but she feels that will all be lying to herself, telling herself she has value just because she exists, etc.

I would love to help her through this but it feels like she stays here deliberately almost. She exaggerates anything painful and minimizes anything good... because she's still not "her".

Any suggestions on how to help her would be greatly appreciated.

Thank you.

I have met many women in this same situation. They are "The Other Woman." They entered a relationship knowing their man is in love with another woman. In most cases, the man is married.

How do the women stop feeling worthless? I always tell them to end the relationship. If we can't handle that we are not #1 in a relationship, then there's no need to continue to be in a relationship where we will always be someone else's leftovers.