Husband cheats but leaves you very unsatisfied sexually what should you do?

It's difficult. She really should have discussed your sexual problems and given you a chance to remedy it or offer a solution. Maybe she just uses this as an excuse for her infidelity. Either way, now that she HAS been unfaithful, it's definitely time for some professional help. Because of her infidelity, you will have some trust issues to work on as well as her cliam of your sexual inadequacy.

Answer

It is an excuse and places the blame onto you instead of her. I agree that she should have discussed the issue with you. It's an excuse.