You know, if you and she now have separate domiciles, then she now has her own bed that she gets to do with however she pleases. Yet that's not enough, she has to have authority over your bed as well?
When she moved out, did she see that concession as a blank check on which she could make arbitrary demands from now on? Is it possible she just really wants monogamy (read: you all to herself), and is going about winning that objective from you by a war of attrition?
Is she willing to settle for the compromise of just using two different sets of bedding?
Love means never having to say, "Put down that meat cleaver!"