going from engaged to roommates... is this a good idea?

I have been with my fiance for 7 years... It's always been a complicated relationship we fight constantly.... I am a happy upbeat adventurous person while she is constantly negative and has anger management issues. Lately ive been thinking about the future, I really don't want her in mine that is. The problem is I care about her well-being she has had a very hard life being abandoned by her parents and being put into foster care, seperated from her siblings, and more recently a man who took her in as his own has killed himself. So as you can see it's reasonable I'm worried about her. I have just suggested we take a step back and become roommates. We won't date anyone else for now but the romance will disappear. Hopefully this will either rekindle our relationship or we will see that we are better friends and go our separate ways.... I just need some guidance is this a good idea and what else should I do???? I still love her just not as a lover more as a close family member.