Outside of alternate timelines, such as Storm in the Age of Apocalypse and again in House of M (where she wasn't interested), or Ultimate Quicksilver (and yes, let's not go there), no he's never showed any interest in anyone other than Crystal, and thus clearly needs to go save her from being married to Ronan the Accuser any longer.

And really, despite the efforts of some anti-talents over the years, it's like Magneto and his children all seemed to bond for life with their first love.