They are just like dating. Everybody puts there best forward. The other person in an affair knows what your looking for. You probaly have told them several times what your problems are. What most of us that have had affairs don't understand in the long run this other person and the relationship becomes just like what you have.
Time does that to most marriages.
Affairs are a selfish acts and only takes away the energies that we should be putting into learning how to love the person we married. Just look at the numbers of failed second marriages. Gotta be a reason, they are no different than the one we just left. I feel like I could be your husband. I was the same way with my wife, plus there were other problems.