Welcome to our forum.
Have you been able to get some professional help for your depression? Counseling; support groups; meds? Is the lack of a substantial physical relationship at home mostly because you're not in the mood, or because your wife's not in the mood, or both?
Can you identify anything specific that's causing you to be depressed? or is it just a generalized feeling? Anything in your past that might have contributed to it?
Does the depression cause you to be introverted? Have you ever tried to make a list of good and bad qualities that you have? Maybe you would be surprised by how many positives there were. At the least, you'd have some idea what to work on and what to build on.
You're in one of the best-supported areas for polyamory in the country, so you've got that working on your side. Sometimes it just takes awhile to find the right person for you.
I hope Polyamory.com will be of some help to you.
Love means never having to say, "Put down that meat cleaver!"