I really hope you can heal from that.

Here's an update of sorts, though not from the person you were referencing...

I was in a really shitty long-term relationship, and it left me with so many hang-ups and emotional scars. Towards the end of it, I had become a paranoid husk of my former self, because he was a liar and treated me really unfairly. He was constantly gas-lighting me, and our relationship was kept secret for years, because he was afraid his parents would disapprove - I felt totally worthless. (There wasn't actual infidelity as far as I know, but he was exchanging naked pictures with women in his state, and I lived in a different country, so I quantify that as a major betrayal. He had intense phone conversations with at least one of them; I don't know how much further it went than that.) That whole relationship and the break-up sent me into 2 years of some of the worst depression I've had, and I thought I was broken.

Afterwards I really didn't know if I could trust someone again because I had encountered so many opportunistic, untrustworthy men, but I did meet someone wonderful and I do trust him. (Unfortunately it's another long-distance relationship, but the fact that I wholeheartedly trust this man should be an indicator of how solid our relationship is, especially in comparison to the last.) I've even been able to use all the lessons from past heartache to help us keep our communications open and healthy.

So please don't give up hope. Work on yourself and your own self-esteem, knowing that even if you never meet someone you'd like to give your time to, you'll be better off than when you started - that effort will never be a "waste". That's what I did, at least, and it led me right to who I'm happiest with.