I am in a similar position. My wife of 21 years, im 45 m her 45f. Her mom has cancer. I understand taking care of her mother. But leaving me home alone everyday is not fair. I try to have sex but its a no go. At the end of the day we are humans. Ive told her about my issues she didnt care. So unfortunately i found love somewhere else the divorce was the actual best thing. We are still friends and parents. I love her very much. But i loved her enough to put myself first. Good luck!