Polaris, also known as Lorna Dane, From Marvel: X-Men.

Needing to marry you.

(I ccouldn't decide to make it. "Needs to marry User to live" "Wanting to repopulate mutants" "Wants to create more offspring", or a WhoreHero thingy where her father died and the other X-men are slowly dying down. SOMETHING... "Needing to marry you to create more children and not to die" sounds good, I think. Think of it as like maybe WhoreHeroes, needing to marry to hide away, and breeding for more offspring/Mutants, SOUDNS GOOD)