It is their mind you genuinely fall in love with. Looks will fade, change. Physical attraction is certainly a part of the chemistry that can add to a relationship. It doesn't form a good basis for a relationship. Will it pose a problem in the future? I guess you could look at it this way - when your both 90 and she has stuck loyally by you and you her. Will it matter or been a negative when you've shared a lifetime of happiness together?