I think everyone is right on with their advice. I would just like to add my 2 cents!
I think when both parties are over-weight and one does something like WLS that the dynamics of the relationship are hit hard, all jealousy issues aside. You have no idea how much food is a part of your daily relationship; your social interaction, your rewards, even your co-dependancies! So that was an interesting spin when Mike had his surgery and I was still in my food induced haze.
But what really woke me up, so to speak, was the changes in our interests, which I think is the part that will apply to you. I don't care what the situation (if one of you goes back to school, loses weight, when you have a baby, gets seriously interested in something new), common interests are what binds couples. And if your interests become too far apart from each other, you have 2 choices. Adapt to show interest in your spouses new interest, or fight it. I think if you have a strong relationship, you try and adapt with your partner. But if things are strained, tense and resentful, it's easier for people to give up and move on.
Growth is a funny thing. It is exciting and threatening, challenging and a burden. Depends which side of the fence you are on!
I'll get off my soapbox now!