Why is it weird?
Aside from Lindsey, Stevie hasn't exactly dated the hottest men around - Iovine, Henley (although I wouldn't have kicked him out of bed in the 70's either), Walsh, Hine, etc.
She obviously connected with Mick. I don't think it was about the sex, quite the opposite. They were in love. God forbid she fall in love with someone who isn't attractive.