Infidelity Support Group
Any relationship in which one partner engages willfully in sexual relations with another outside of the partnership is considered to have experienced infidelity. This breach of trust is often traumatizing for the faithful partner as well as the relationship, and support is often needed to heal emotionally and to decide whether or not the relationship should continue after...

I think I am a pro at infidelity now because I ve been cheated on by 3 different serious partners - exH, fiancé and bf. All of the 3 situations had nothing to do with sex, although sex was involved.
Sometimes people cheat because they are unhappy at home and because the sex is bad. Clearly , this was not the issue in your case.
The third reason, in my opinion, are some unresolved conflicts in the cheating person. Anyone could be in your place - a model, a brain surgeon, just anyone, and that kind of partner would still find a reason to have an affair.
Some people just need the fantasy, the risk of being caught, the Desire to be wanted by someone, the need to be whoever they want to be in another person’s eyes, not the person you really know them to be.
Unfortunately it is some kind of a psychological plague.
I took back my cheater boyfriend recently and I am still anlyzing everything in couple’s therapy.
I m starting to think that it is not worth it.
We should be spending our time being happy, not agonizing over these liars.
Hugs. Wishing you healing and love.
"Some people just need the fantasy, the risk of being caught, the Desire to be wanted by someone, the need to be whoever they want to be in another person’s eyes, not the person you really know them to be. "
When we were talking before I left he did say that maybe he wasn't meant to be in a relationship. I suspect that's the case....... we tried.......sigh
He wants to do this, he likes doing this, and he thinks he can just lie to you - be super, duper sneaky and keep doing this.
You have to decide what you next move will be because it is pretty doubtful he's going to stop.
The level of character and emotional health to sustain a lifelong relationship is rarer than most would want to admit and you need 2 of those people in the relationship.
The level of divorce and adultery in society proves this truth.
You ex-partner is just on the wrong side of the population and hasn't been able to change since the last time you caught him overseas.