I agree. The key to me was the comment about sleeping ten hours per day, which is not normal. Depression can be the result of weight gain and feeling bad about yourself, or of a spouse displaying displeasure by “encouragement” to join gyms and such, increasing the poor self esteem. I wonder if the OP’s encouragement to go to the gym, go walking and hiking, might be perceived as nagging.
My wife is not the same slim physical beauty she was when we married, and I, though the same weight, have my own physical issues. But when I look at her I see the most beautiful woman I’ve ever known and I tell her so frequently. The time we spend together is precious. She is the love of my life. We both change as we age, and adapt our lives to make it work. I had a period of depression and she stood by me during the rough times and saw me through it. I’ve stood by her during a serious cancer battle. If she tries to lose weight, I stand with her and eat the same foods. She’s had knee replacements, so long walks are difficult for her. We adapt. We are extremely happy. I pray the OP can find similar happiness.