From highs to lows, relationships don't feel worth it to me

You sound like you are burned out on love, sex, dating and relationships. You're not alone! There are plenty of other men, and women who are burned out on this stuff as well. Don't blame yourself, but don't play the victim to yourself either.

I'm actually in a place in my life that is not dissimilar from where you are. I can't tell you what to do, but if I were in your shoes I would try to focus on myself, and on self-discovery. I would, if I were in your shoes, seek to discover what it is about me that attracts these sort of people to my life, and or why am I continuously attracted to these sort of people.

I can't force you to change your approach with women, but I will tell you that an ex is an ex for a reason. Once a cheater, always a cheater! If a relationship doesn't work out initially with a particular person it's no more likely to work out, just because ya'll have broken up, and suddenly feel lonely, or because she says she misses you. Always remember that actions speak louder than words, and people can promise you the moon when they can't even give you a streetlight.