Dovrosenbaum
I think you are simplifying the rules about how to treat a convert.
Obviously, if a ger behaves poorly towards you, you don’t have to become a shmata and take it.
I believe the halacha is that a person is not allowed to remind a ger of his past and his family/religion of origin. That is what is considered Inui/suffering.
To say it is forbidden to have machlokes means that it would absolutely be impossible to be a spouse to such a person because every marriage has some machlokes. It’s the desire and willingness to work through them that maintains marriage.