Hi hon.. I think this is a common fear for a lot of people.
WLS can affect relationships but from what I've seen and from what other people have said what it seems is that the good relationships tend to get better and the rough relationships tend to get worse.
There does seem to be a rather high divorce rate reported after WLS, and I know that anecdotes don't mean much if we're talking statistically, but it seems that those that divorce often had trouble in their marriages prior to surgery; statistics just don't allow for reasoning behind the situation, you know?
"They" say (not really sure who 'They' is, lol) that often an obese person has a tendency to settle for someone who isn't really their true love. This doesn't sound to be the situation in your case, though so I wouldn't worry about it.
I'm thankful that even though I met my fiancé while I was obese that he is not at all worried (or at least doesn't voice those worries, if he is).. I remember when we visited my office a few weeks after my surgery and one of my male coworkers says to him "What are you going to do when she loses the weight and gets sexy?" and Geof replied "what do you mean GETS sexy? She already is!" Ahhh.. gotta love that man
Sounds like yours thinks similarly