A strategy i used was to distance myself. I cut contact to take care of myself and my mentality. Even when they would ask me why i wouldnt talk to them, i would be straight up and tell them exactly why. One of the most important things is to make sure they know what they did wrong, which helps them realise that they can either let you go, or they can take the steps to change themselves.

My biggest pain is not being able to supervise as much as i would like to, due to the distance. Sometimes it can be hard to know if the company is doing everything right and according to the idea i have in my head.

In this case, the best option would be to end the relationship. If they have cheated multiple times, it shows you that they dont care about you or your feelings. its hard to accept that your partner doesnt have enought decency to give you even the bare minimum of being loyal but if you really care about yourself, you should make the decision and leave the relationship because you cant make anyone change.