I wonder how much of this is depression and how much is mid-life crisis. I look back on my life and say, "Man, what missed potential!" I haven't really done anything with my life, either. I've been married for 22 years and I find myself in the same boring marriage place as OP...and it's about 75% my fault. The other 25% is my wife's unwanting to really do anything. So I do like OP and spend most of my free time in front of my computer. It's one of the reasons I started getting back into comedy and doing improv.
I have no friends. I know OP says his friend have ignored him, but I'm in pretty much the same point. My friends all moved away. Those who remain don't see me. I've hung out with some work "friends" but if we didn't work together I'd probably not hang out with them.
So why am I not doing the same as OP? Because I try and find things outside the house to help my mental state. I joined a softball league. I'm in a couple fantasy football leagues, I do my comedy. It gets me out of the house. Yeah, I like sitting around in my underwear playing Skyrim, but I know it's not good for me.
What concerns me is the suicide talk. I know it's almost cliche, but you need to get to therapy. Your wife's reaction is problematic, but she probably thinks you are whining and not really feeling this way. To her you've probably always been a rock of strength. She might not be able to fathom that you have this weakness. When you go to therapy she'll probably realize how serious you are.
So. Go get therapy. If your wife still gives you the man up talk, get her to join you. Oh, and check with your work and see if they have some sort of mental health care. You might be able to get 3 or 4 visits for free and see if it's right for you.