Does she have an anxiety disorder? That sounds more like anxiety to me. Anxious people are always afraid of change. I'm sorry you're dealing with this with your fiancé (Genevieve is a pretty name by the way!). Has she had a bad past with moving in with partners? I'd say maybe she needs to talk to a therapist to address any underlying issues. Is she on meds? Is she depressed or manic right now or stable?

Sorry for a million questions! I really wish the best for you two. ❤️