It makes sense, I am curious, though. Have you two worked on your connection? Since she has been feeling distant for 4 years if not more, have you sought counseling or tried to reconnect in any way? Has she shown any interest in trying to reestablish her physical interest by trying to figure out the cause of her interest waning?
My main concern is that you are doing this just because you're lonely. Even though you say your wife is non-responsive, have you thought about how she will react if/when you DO find another relationship?
The last few days, I have been all about telling people to do what they need to do, but you have to be willing to deal with the consequences. I'm not telling you that seeking a poly relationship isn't the course for you, and I'm not judging you at all, but I'm just concerned about the state of your marriage and how it would affect any additional people who you bring into your life.