Conflict with husband

My husband says he doesn’t feel like I’m “in to” him. This makes me feel guilty and that I’m letting him down. I do love him and we have an OK relationship overall, but I’m not super attracted to him. I always feel like I am disappointing him, and this has been a consistent feeling throughout our 20 year marriage. I guess this is the model:

C: husband states he is unhappy with our sex life
T: I should be able to make him happy. There must be something wrong with me.
F: shame, guilt
A: avoid, withdraw into self
R: no growth in relationship

I try new thoughts like “I’m not responsible for making him happy,” but it doesn’t feel true. I guess deep down I still believe my thought. How can I move toward new thoughts?