I'm a guy, was married 27-28 years when I started toward surgery. My wife was like you, outgoing, social, etc. I am like your husband, introverted, insecure, a curmudgeon. Ok, here we go...
I've heard it said "WLS makes good marriages better and bad marriages worse."
My wife supported me 100%. But I initiated a similar discussion. Since I was always huge, I couldn't be sure that I wouldn't change. What if I did? We finally decided worrying about it doesn't and won't change anything. Worrying now (then) was wasted energy. I had no intention of allowing WLS to kill my marriage and we had to settle there. It wasn't just one discussion, we had it several times before and after surgery. Each time we reconfirmed our commitments to each other.
Unless your husband is typically a jerk to you, I wouldn't count his insecurity against him. It's a fair concern. You both have issues and you love each other. But, once you remove your issues he fears he won't be good enough for the new you. Talk about it. Reassure him in no uncertain terms your feelings and intentions. Each time it comes up. Affirm your feelings toward him.
If he is a total jerk, well surgery or not you have some thinking to do. My experience won't help you here.
For the record, our marriage got better. My insecurities about the new me didn't blossom, but I'm still insecure. I am still me and I'm still in love with my wife more every day. She reports the same... but I think she's just being nice
Good luck
Tek
PHAT Girl reacted to The Greater Fool in Painted in a corner--marriage issue
PHAT Girl got a reaction from tarotcardreader in Food Before and After Photos