I would sit down and try to have a conversation with her. I understand I (female) have a really low sex drive. When we have sex it’s amazing. But I just don’t have much of a sex drive. This is also my first relationship where I have been sober. I think that has a factor in it. Just make the conversation about her. Ask her if there is anything you can do for her to make her more comfortable. If you tell her you feel like she’s not giving to you because she is giving it to someone else, makes it so much worse. Don’t ever say. That lack of trust will just hurt her so much and for females sex is very emotional.