Hi Mula... sounds like you have both given up... and unless you talk and work things out together you might as well do.
Sorry if that sounds harsh, but its the way I see it. I was married for almost 42 years...my OH died 2 years ago... and I still loved him and miss him so much. Be glad you still have yours... get some communication going.
It takes 2... dont be resigned to the way things are, its nothing to do with the kids growing up... I do hope you havent centred your world round them and forgotten about OH ... it does happn.
Sorry if I am not saying what you want tp hear, but be glad you have a husband, even if he sounds as unhappy as you. Grab your lives back while you are still young.