Low sex drive!?

Recently, I've had a very low sex drive, and my boyfriend accused me of cheating on him. And I'm not. He said that when we do have sex I always look away, and that I'm imagining it being someone else, but once again... I'm not. I don't know what to do anymore. I just don't really want sex much anymore. I feel like it could be because our relationship has been rocky the past few months.... But I'm not sure.... Please help😞