well, I remember when I was depressed and not doing well, and how I felt.

Forcing someone to go get treatment ... do you feel like she's a danger to herself / others right now? I agree with Amyscience that you can't force her to do anything unless there's a legal way to do it.

So, it all depends on that.

Is she going to therapy? Is she getting treatment? You could work with her treatment providers if so, and if not you should try to get her to seek treatment. In the end it's her option to get better... her choice.

I remember once my ex-bf called the cops on me because I left his apartment and wouldn't call him back. I was angry at him and didn't want him to control my life at the time - and he wasn't giving me space. It was one of the most embarrassing moments in my life. And it made things worse, not better. That being said, if the fiance is really in danger it's more important that she stays safe so she CAN get better than the other option.