Married, yet so very alone

Sorry this is so long but I'm honestly not sure who to turn to anymore. I have no one to talk to and my marriage is now killing me inside. Writing this is a first for me.

I turn 40 tomorrow. I've been with my wife since we were 15. Typical family setting, three kids, dog and a cat. Like all marriages, we've had our ups and downs but no matter what, always stuck by each other and worked through whatever life threw at us. Love was never an issue, intimacy was never an issue. We've always done everything together, rarely ever apart. We were very social and had plenty of great friends that we would go out with at least once a month.

Then in 2019 she started getting a little detached. She had some health issues and her mother was diagnosed with cancer at the time. Understandable that she was stressed and depressed so I did what I could and gave her comfort or space depending on her needs. Things seemed to turn around a little for a few months, and despite the pandemic, we managed to purchase our dream home in the fall of 2020. Her mother passed away a couple months later and it hit her hard. Having lost a brother in the past I know how hard it is to lose a family member. I continued to be a caring and supportive husband.

She started to become detached from me and our friends and no longer wanted to socialize (not covid related either). The intimacy disappeared and she started treating me like a chore. No more happy to see me after work, conversations went from heartfelt discussions to 3 minute "finish your thoughts before I finish my cigarette" situations. Sex was always consistent and fantastic but has now become a weekend only "15 minutes or your done" chore to her and she makes absolutely no effort to instigate or even participate. Most of the time I can't even force myself to enjoy it because her face clearly shows she's not interested. She'll just lay there, won't even attempt to touch me, or even wrap her arms around me for that matter, and foreplay (which was always common) is now non-existentant and taboo.

We always went out of our way on birthdays and anniversaries to do something special for each other. Now she doesn't even acknowledge them or even worse, for my birthday last year she gave me a card that basically said "sorry I'm not loving anymore. Happy birthday roomie". Yes she used the word roomie like I'm some college roommate. I got her an amazing family portrait for our anniversary and set up a scavenger hunt for her to find it. She got annoyed she had to work for it and when she was finally presented with the gift, she showed no appreciation and never even bothered to tell me happy anniversary.

We no longer go out with our friends at all, most have moved on after themselves trying desperately to do things with us but she won't even bother to respond to them half the time. She gets upset and passively punishes me if I go out by myself. My job sucks and I work remotely so I never see anyone but her and the kids. Pretty much zero interaction with the rest of the world so since I no longer go out with friends. I looked forward to seeing her every day regardless of this.

Now it's just depressing to be home because she no longer brings any joy to being here. I've tried talking to her about it several times but that only makes things worse. She denies being depressed, knowingly avoids intimacy, and treats me like more like I'm a bill paying tenant instead of her partner. Could care less if I'm in the same room with her but gets upset if I'm not around to take care of something for her.

I deal with all the house chores/repairs, all the kid's extracurriculars, as well as maintaining the pets, on top of a rather stressful and busy career. She has her own career and cooks dinner. Now even dinner is too much and complains I should make it because I do not do enough. I seriously do almost everything around here.

It's like my entire life has been upheaved and thrown into the trash. I've never been so lonely, mentally frustrated, sexually frustrated, unappreciated, and helpless. I don't want to leave her. I still love her to death but I'm at my wits end. I don't know what can be done. I've tried to tell her my feelings and it always ends with her giving me the cold shoulder. She'll just stop talking to me altogether and avoids me like the plague. I've asked if she needs to go speak with someone other than me about her mother's passing. She gets upset if I bring it up and tells me that's not the problem and doesn't believe there even is a problem despite all my efforts to explain.

I'm completely trapped. I can't leave her, but living with this is driving me to horrible depression. I want to run away but can't. I'd never do that to my kids anyway. If I was to tell her I need space and we need to separate, she'd take the kids and everything else with her just to spite me. She's not a mean person in the least but since it wasn't her idea to separate, she'd take everything away just to prove that my decision is the wrong one.

Everyone else sees this as well. It is not just me. Every person that has brought it up to her, she has stopped talking to. Our friends now don't want to intervene because they don't want to lose me as a friend and are afraid it would only make things worse as well.

I need help, advice, anything that will make me stop feeling like the best solution to my problems would be a fatal car crash that my kids could collect on to cover my funeral expenses. That's where I'm at right now. I love her so much I'd rather be dead than have to go another day being married, yet completely alone.