I know of many couples who play together, varying from those with separate mains who share a single computer to those who sit side-by-side and take part in the same raiding guild. I also know of relationships where only one half plays WoW, though it hasn't caused any break-ups as far as I know. I think either can have its happy moments.
My other half refuses to play games at all, but we share so much else that having a few different hobbies makes life more interesting. He listens patiently to my babble about dinging and a good night's loot, which is about all I could ask for. Does your partner put up with WoW with gritted teeth, or with a smile?