Definitely ask your boyfriend if you can be in charge of feeding tie when you are there. Figure out what kind of toy she likes, and try playing with her, especially before bedtime.

One crucial thing is be as relaxed around her as you can, try not to project nervousness. Ignore her as much as possible when she's being naughty, don;t reward bad behavior. And maybe try spending time when he's not around, just being with her. Patience, patience, and if she likes pouncing, fish-pole type toys that are okay to pounce on! Does she have a cat tree where she can get up and away from you? That can be helpful, so she has a space you cannot "invade" but is just hers.