There's nothing wrong with you. There's been research (no source) that men evolved to be more monogamous than women. Women tend to stick to their children regardless of their partner, but men require the tenancy to be monogamous in order to keep the family together. Monogamous families survived and those who weren't died. Male monogamy was passed on, there was no need to pass on female monogamy, as females lose a lot of value the sex market once they have children.
That runs counter to the notion that men like to cheat on their wives when it's actually women who are preoccupied with their own sexuality and are more likely to just up an leave. If it weren't for children and finances, there would be way more instances of women filing for divorce. Men usually cheat because after two or three babies the wife just doesn't want to have sex anymore, I've seen it happen.
I don't fully endorse that (unsourced) research, but it correlates with my experiences well. I've known so many more men who've had difficulty moving on from a relationship than women. Women are worried that they won't find someone else who can do as much for them as their previous partner, whereas men just want their previous partner back at all costs, including complete destruction of their lives.
Maybe I'm sugar coating it. Men want the most attractive women and women want the most productive men. If the woman isn't attractive, men'll cheat. If the man isn't productive, the woman will leave. Maybe that's the truth, I don't know.
Sorry if it's off topic. Just some things to think about. There's no such thing as normal. Just try to live your life as well as you can.