Janet,
Something to consider from the "guy game" side, keep improving yourself. Regardless of what the future brings, being the best YOU you can be is always the right choice.
Now, admittedly, the improvements on you may not make her want to be your wife more.... But there's still the possibilities of friends, even lovers, even after transition. Don't know how exotic you might go, but lots of options can be foud with Google and a devious mind.
Where do you want to go factors into it, too. I wouldn't ever suggest someone stay and be miserable. Its unfair to both sides.
I'd also take a detour here... Gastric bypass don't mean %%=\ if she doesn't bust rear to lost the weight. If you have the capacity to meet bypass surgery, look into the Velocity diet as a dry run. Talk her into it, it's important she learn how to handle that sort of eating... Because as I understand, the surgery is irreversible. She might realise she wants real food more... Velocity is only .want to be 4 weeks. I've lost a grand total of.... 5 pounds. This is week 4. And I was losing nothing until I started daily exercise as well. As far as snacking? Not much. Week 3 end, we had a cheat day. Burgers were good... The woman, currently doing PT for a torn meniscus, has lost about 10 pounds the whole three weeks and counting. But, she's doing better eating, and that was my goal with her.
Next step is a ketogenic diet 5 Days a Week, and a healthy re-feed day one day as week. Hopefully some exercise, but with her knee, we'll see.
Establishing the habits will help bring you together, and maybe take her off the surgery option. If nothing else, you can go looking for men together, even if you're not interested. ;-) Be a good wing-girl, right? ;-)
Options to consider, that's all.
Hoping for the best for you,
-Dianna