If you enter a relationship, and have a tiny contingency plan; relatives you can visit and stay with, a private bank account, activities, then his adultery will not take your ‘whole world’.
This is what you are guarding against; being so devastated you make stupid decisions and ruin your life.
Guard against becoming the woman whose husband cheated on her twenty years ago so never had another relationship.
In some cases you can survive the adultery and give yourself carte blanche; meaning if you want to have an affair, well… he already broke the vows.
In some cases you can excel at work because you have nothing to rush home to.
Whatever decisions you make, don’t let them be mindless hysteria.