How do you handle double standards in a relationship?

It depends on the double standard. Men and women are not the same, so sometimes exceptions need to be made for the one or the other that would never apply in the reverse case. But if it's a double standard where the relevant standard is "person" rather than male or female, I refuse to abide by it. In a relationship, she would have no justification for using such a double standard against me, nor I against her.