I'm so sorry that you have to deal with this. Especially with being close to surgery date and all the emotions that come with that on its own.
No one can tell you what the right and wrong decision is, but we can support you in whatever you decide.
All I can suggest is that you be honest and true with yourself. You CAN do this on your own, and you won't be alone for the rest of your life. Find who you are, and what you want. You deserve to be treated well, and you deserve to be able to trust someone fully. The trust with your husband is gone, it will never come back, no matter how hard you try to move past it, it will be that nagging voice in the back of your mind for the rest of your lives together. I've been there, I know it all too well. I tried to forgive my ex-husband the first time, but after the second time, I was done.
Your life is about to change in ways that you cannot imagine. Your weight is going to melt off of you and you have a whole new life ahead of you. I ended my relationship with my BF about a month before surgery. I was sad in having to go through the journey alone, but now, I realize it was the best thing because I only had to concentrate on ME.
Hang in there hun. Take the time to seriously think about what you want. Just know that you deserve so much more!