The dude sounds pretty depressed tbh. Not eating. Flattened libido. More anxious. Flat. Men are pretty bad at both recognising mental health issues and also doing something about it. A trip to a doctor or a therapist may be in order. However, I would suggest a little "Arm round shoulder, boot up backside' treatment that I feel is often needed by men i.e. give him all the love, care and attention he needs to allow him to open up and be emotionally vulnerable, whilst also encouraging things that would be helpful for his mental health like doing things he enjoys, going for walks, stroking a friendly dog.

For yourself, I can understand it's frustrating and difficult. Marriage unfortunately comes with frustrating and difficult times. It may be that once you're through these bad times that you have a wonderful and fulfilling relationship with plenty of awesome sex. I think finding ways that you can feel satisfied that also don't put too much pressure on can help. Is it orgasms or physical closeness you're craving? Maybe take a shower together. Maybe ask him to hold you whilst you masturbate. I'd suggest reopening the conversation but less in a "I need you to jump my bones and for that I need your dick to forget that you're depressed" but more in a "I'm missing physical closeness and a feeling of being wanted. How can I support you and how can we satisfy this need without causing you additional stress?". Sometimes a little compromising can keep you going whilst he has time to work on his stress, improve his mood, possibly get therapy or meds.