This is good progress and I am happy for you. I hope you still continue to speak up when you need him, and don't let your empathic nature, and feeling bad for her, get in the way of asking for alone time with your fiance. Having her there 5 nights a week seems like an awful lot, especially since you are the fiancee and dealing with an illness. You don't need to put her needs before your own, just remember that.
I just say this because I keep getting the feeling you would rather let things be all nice and smooth on the surface, rather than have to rock the boat by limiting her time with him. You should be allowed to voice your concerns and she should understand that you have needs. And yes, I think it's a great idea for you also to surround yourself with other loving people in yoru life who can also help with what you need.