If a man and a woman have a love for God in common how many more interests do they need to share? I mean take mixing colors together, if you mix blue and blue you get blue, but if you mix blue and red together you get something new! Purple I think...Another, maybe better example, mixing copper and copper you get more copper, but if you mix copper with tin then you get bronze, something stronger and prettier to boot.
The problem for guys is that a virtuous woman is rare. The bible says they are worth more than rubies. So they are hard to find, cost alot, and if you aren't careful you might just end up with a red piece of glass instead of the real deal.