Sex advice with Suzi Godson: My younger partner seems insatiable

If you are willing to be honest about how you are feeling, you and your girlfriend have as good a chance of working things out as anyone else.
Being 15 years older than her doesn’t preclude you from admitting to insecurity, and sharing your concerns sets a healthy precedent for honest communication. Your girlfriend may even be relieved to know that you want a night off occasionally.