caught partner in bed with a friend

[Virge]

you sleep upstairs? He sleeps downstairs?

That alone says things don't seem to be what they should have been. It sounds to me that the relationship was already headed downhill.

Others have already given you all the advice that can be given.

If he comes back at you asking for forgiveness there's something you might want to consider.

Sometimes giving forgiveness is the same as giving permission after a crime has been committed.

[Iceblink]

This has to be over after this. You are moving out of country and there is no way you can risk taking him with you. What happens when this happens again in whatever country you are returning to? Most of us would just kick him to the curb, but you've gone into this with knowledge of his not being trustworthy, so what do you do? Like a landlord that keeps accepting late rent every month, sometimes your actions give permission despite what your words of agreement may be.