Her "lacking interest" is what hurts the most. I have tried talking to her about it numerous times. She just does not care.

In that case, sounds like more drastic measures are required.

There was a post in the DeadBedroom sub that might help:

The long hard road, out of hell

About two years ago I posted this and this. Lots of other terribly depressing stuff too. My life was shit. I frequently dreamed of suicide. My biggest problem was my sexless marriage. I logged in to this old account this morning to find a dozen messages asking me if I had killed myself (How would I even answer?) or if I had divorced my wife yet. Neither of those things happened. Something much better happened. Prepare for a massive wall of text.

Shortly after I made those posts, my wife and I started seeing a marriage counselor. Everyone in the world told me counseling was the right thing to do. I really put everything I had into it. I stuck around for one year, but it was completely worthless.

The counselor's advice amounted to something like "So you're horribly depressed because you have needs which aren't being met. Have you considered not having needs?". At one point he floated the idea of trying to get me a libido lowering drug. He was 100% on my wife's side of everything. Really just toxic and not good at all. Seeing him messed with my mind. It almost made me believe that sexlessness was the normal state for a marriage and that I was some kind of deviant for wanting to fuck my own wife.

After visiting him for a year, for meetings which consisted of my wife chewing me out for something trivial, while he cheered her on and I sheepishly apologized, with no progress towards breaking out of my sexless marriage, I told him to fuck off. I told him that his services were worthless and that I would not be returning.

At this point, I was completely out of fucks to give about anything. I quit caring at all about my wife's needs. I basically just pretended like she didn't exist. No dating. No little gifts when I went on trips. No celebration on her birthday. Nothing. As far as I was concerned, she was invisible. I had spent YEARS caring about her needs while she didn't give a shit about mine. It was time to rectify that balance.

Instead of focusing on her, I focused my energy into myself. I got back into old hobbies I had been neglecting during my depression, started spending 3 or 4 hours a day at the gym doing heavy compound lifts fueled by repressed anger, and running until I made myself puke. At home, I'd channel my attention in to maintaining a clean bodybuilder's diet. I completely eschewed alcohol.

My schedule basically went something like:

• Wake up.
• Go to work.
• Get home from work.
• Change clothes.
• Leave again.
• Come home hours later.
• Go to bed.

On an average day, I'd say maybe ten words to my wife.

Nothing changed at first, but I cared much less. Being able to completely destroy myself at the gym helped resolve a lot of the emotional problems I had. Depression can't stand up to a heavy pump. Plus I was getting fit enough that I would occasionally catch other women checking me out. People who worked at the gym kept complimenting my work ethic and my progress, which raised my self-esteem sharply.

About three months in to my new lifestyle. My wife stopped me at the door while I was leaving and said she wanted to talk. I said "I don't want to talk to you. You know what I want." and I left for the gym. The next day as I was leaving, she stopped me and said pretty much nothing before initiating sex. That day I missed the gym because we fucked for four hours.

Starting the next day, I'd text her commands from work. Stuff like "Be naked when I get home." or "Wear the red one. Make sure a lot of lube is easily available." and she would follow them. I'd make stops at sex shops on the way home and buy whatever looked fun, without consulting her.

For about a month after, I still spent no effort on her needs. She had a history of promising sex, if I'll just fulfill some condition, and then moving the goal posts when I did. I didn't know if this was a real change, or if she realized that all her power over me was gone and it time to either put out or get kicked out and was trying to reestablish the control she previously had.

Every single day of that month. Sex happened whenever I wanted it, for as long as I wanted it, however I wanted it. No resistance. No complaints. No being too tired or not being in the mood or whatever other nonsense. Just fucking.

After that month, I figured that our change was permanent (or at least had gone on long enough that it wasn't some kind of trick, and I could act on it). I started rewarding her for putting out. I started taking her on dates again, and playing card games with her again. I'd bring her little gifts again. If she didn't put out on a given day, for any reason, I'd completely deny her any of my attention or energy.

This change in our relationship has lasted 9 months now. She's very nice to me now, gets naked whenever I want, and is super affectionate in public. I love her again, and now I feel like she loves me too. My depression is over!

tl;dr: Ignored my wife. Worked on myself. That fixed my marriage.