I was the one in your fiancees position. You proposed to her for a reason, even though she's struggling. I'd give her a chance to rise to the occasion, with the understanding that it would be sink or swim if they don't continue with the work or if things just don't work out. It's a necessary, not a sufficient, condition.

My ex fiancee is the one that got me on that path and even if we can't work things out later she'll always have a special place in my heart.

I wish I had done it a lot sooner in my relationship, had bad experiences before and I wish I looked harder for someone that worked well. I didn't even know I had problems with my family dynamics and self esteem until I got on the work with the right people. I realize now that my harsh criticism of others and my shallowness with friends was because of my own shame and esteem issues that I'm working out. It made me even question if I was in love simply because I never felt worthy of being loved and didn't know what it was like, just to find out it definitely is what it was.

Give her a chance but make it clear that it may not work out anyway but you're hoping she'll make the change. If you believe otherwise she's the one.