I have Anxiety, Guilt, and Depression because I want a different life than what I have

I have a wife that I love and 3 step children who are almost all grown. My wife also has a Multiple Schlrosis type illness. Our relationship is mostly spiritual and intellectual....we never have sex...that has just never really interested me. I tend to be A-sexual. She, however, has an extremely high sex drive.

I have anxiety because I fear she will want to leave me or replace me...we have agreed to an open, polyamorous relationship, which I don't really believe in but allow because I feel it's not right to deny her sexual fulfillment just because I don't want sex.

I have guilt because I feel I would be better off on my own working seasonal jobs in National Parks and resorts and thru-hiking the Appaachian, Pacific Crest, and Continental Divide Trails. This conflicts with my anxiety, obviously.

And all of this...my whole life situation depresses me to no end....some times I just want to cry uncontrolablly and block the whole world out and forget it exists.

I don't know if anything can help or if I can expect anything different than the life I have.