Husband has had a gun and kept it a secret

I found out that my husband has a gun and has been keeping it at a cabin we own for vacations. My husband has never told me he had a gun and it's we've never discussed getting a gun. I asked why he had one. Especially somewhere that's an hour away where he can't access it so it can be for safety purposes. He didn't want to talk about it but eventually said he bought the gun in case he chose to commit suicide....

I asked was he depressed? Did he hate his life? He told me not at the moment but he was at a really low point when we had our last daughter and didn't say anything because I was healing from a C-section and going through postpartum depression. He told me the reason he keeps it is because it's comforting to him that he has a way out if his feelings get too much but claims he would never kill himself. I asked "If you would never do it why do you have it." He keeps saying he likes having the option and it's comforting. How is knowing you have a gun to kill yourself comforting? He's always been the happiest person I know. I didn't know he had such dark feelings. I don't think having a gun is the answer and I'm terrified I may wake up and he's gone and ended his life