What are you talking about? I currently have her in both band and home harem.Ok I just found out the hard way that you can't have Sasha in two harems so decide early on whether you want the band harem or the home harem
Did you collar her? She cares much less about cheating if you make her a collared sex slave. You also need to make sure that all the other potential harem members also have the right stats at the moment of triggering said harem.
Personally I waited until I had successfully triggered the band harem first before I then followed it up by triggering home harem. Heh it made her reaction to discovering I'm fucking Bree amusing given that she was already sharing me with her band.