She might not need or want help and her not wanting/not being ready to move in together might have nothing to do with having bipolar disorder.
Plenty of people with bipolar disorder live with their partners so honestly I don’t think it’s a feature of the disorder, it’s not common. Perhaps her doubts are due to something else
We total strangers cant really tell someone we don’t know to move in with a man.
When are you getting married and how long you’ve been engaged or knew each other?