My Husband's uncle David

My husband is like his father a work acholic and as we already had 3 children, he neglected me sexually. His father's youngest brother David 55 is the opposite to them, prefers having fun to working. Single and fit he always enjoying himself and that annoys his brother, but after years of trying to change him has given up even trying. David is quite helpful and came to assist me when my car had broken down. My husband being out of town at the time, I got on very well with David and could speak to him easier than to my husband. So, with my husband always distracted by work and not sexually servicing me. I got horny and 42 with tubes tied, my meetings with David became sexual and still are today. I believe it okay to fuck my husband's uncle as my husband neglects me sexually and I'm keeping it in the family. It's just sex and no relationship other than the family connection and I enjoy the sex. My husband sometimes wants sex, and it is becoming rarer and rarer. I at first thought he was having an affair, but he isn't he is more interested in making money than sex. He has to work to get more and more money, sex he only has to ask. Maybe I should start saying No and make him work at it, but he would probably not bother it that was the case. So, I haven't tried that as the little I get is better than none at all.