My theory for why we didn't have HB is simple. We weren't having much sex before the A. Our sex life had diminished over the years. Every time we did have sex I told him I needed more connection, I needed more emotional intimacy, I needed him more present in my life. It was hard for me to want sex without those things. But he would forget about these needs and then get pissed off that I didn't desire him.
Then I discovered the affair. The last thing I was interested in doing was having sex with him. Why should I reward him for all those years of not meeting my needs. Why should I reward him for having an affair. And then I found the affair was with one of my best friends and that all that time when he wasn't present in my life, he was present in hers. He took my support and strength but did t give any back while at the same time he was consoling her. So in my mind HB was out of the question.
What has helped since then is rebuilding that missing intimacy, being present in each other's lives, breaking old habits and really trying to understand each other. Reading the "Sex Starved Marraige" was also helpful. My WH truly did not believe there was such thing as a low libido person or that some people, like me, don't have earth shattering orgasms every time. His experience was sex was always the best thing ever so why wouldn't i (his AP could orgasm at he sight of a penis so his affair did nothing to educate him). The fallout from the affair finally opened his eyes to me and my experiences and we are slowly rebuilding our intimacy. Based on what I've read here we are no where near what some people consider a necessary amount of sex but we are better than we were and are rebuilding.