Magdrox
Fuck Professor X, accidentally paralyze him, steal his sister and spark his descent into drug abuse. Get locked in a concrete cell for ten years, try to kill Charles's sister for the good of mutantkind, then find out you fathered the young man who broke you out of prison. At that time, the complexities of your romantic life may be sufficient to warrant my attention. Until then, I am far more concerned with your personal freedoms and the survival of your species than who you're sleeping with.
If both women were aware of the nature of your condition, explaining your behavior should be simple enough, should it not?