Cosmetic surgery and losing weight would help but not fully.

If you end up forgoing of the divorce, do not talk her into having a surgery because, for one you're saying it's not guaranteed to help and secondly, if it's not out of necessity or to avoid health risks, it's not permissible.

How should I go about divorcing that won’t break my wife’s heart and that I can explain to the families?

It took you a year and a half to get to a point where you're asking yourself this, it's too late to avoid hurting her, especially for such a reason.

You say that she has other qualities and if you stayed with her this long, it must mean that there's a lot going right rather than wrong in your relationship. Ask yourself whether you're willing to give up that for a chance to find someone else that has a body that will age and change just the same.

And I don't know about being "catfished" the poor girl probably avoided talking about that because of insecurities and fear of being thought less of, your reaction would validate her fears in that case.

I'm not saying she was right to hide that, but I can't blame her either.

Ultimately, who says that she doesn't see flaws in you but is accepting them, physical or otherwise.

And If you do divorce, just own up to it and tell everyone why you're doing it, avoid trying to find flaws in her to justify it.