I think its wonderful that you are here asking questions! You must indeed be in love with her to take the time to educate yourself on her disease and try to find a way to help her.
I think knowing about the disease is very important, however, I think you need to be careful of thinking of her disease as who she is...it is a part of her, but it is not her!
I don't really know what to tell you on how to get her to understand you want to help, but I think it is important to talk to her and ask her any questions about her specific effects of the disease, let her know you care and want to lend her support without "babying" her...although we all love a little "babying" now and then.
If she isn't on the site, you might mention it to her, and tell her how friendly and suportive we can be to her if she needs it.
Mostly I think you need to let her know you understand that she isn't up to her usual antics, but that you understand. Let her tell you what she can and cannot do, but be aware of her...don't let her push herself just to try to keep up, exhaustion is our enemy as is stress.
Do little things, bring her a bowl of soup or fix her favorite breakfast as she probably isn't up to cooking...straighten up a bit, wash the dishes...just a little at a time, but it can mean a lot to have someone help out that way.
I'm sorry I couldn't offer any more, I wish you much joy in your relationship and I hope you both can weather the storm...its very tough.
Welcome and come back often, join us in chat if you need to.