NW1 - welcome to the board. Sorry you are here though. There are a lot of guys here that understand what you are feeling. Yes it sure is a tough feeling. I hope you will find here that you are understood and that your feelings are validated. Logically it might seem like the wrong thing to find a lacking sex life such a big deal, but believe us that it really is.
Time to start working on it with your wife right away. If you don't, it really can be a marriage killer, no matter if everything else seems ok.
Also take heart from some of the people here who have been having recent success...there is hope for at least some of us.