My husband and I were pretty rocky a couple of years ago too. He had an affair with his long lost love, and didn't want to have sex with me anymore. We had had a good sex life even when other things were bad up until that point. But after the family took a stand and made him lose his girlfriend he tried to put me on ice.
I put a lot of effort into seducing him back, even against his protests. I was lucky in that I was able to prime the pump, so to speak. After that, it was only a few weeks until the Retrouvaille weekend that we went to. It was the dialoguing at Retrouvaille and sharing our feelings about our lives in notebooks that rebuilt our relationship. The website for Retrouvaille is http://www.helpourmarriage.org. We followed their advice to the letter and more than rebuilt our relationship.