Ambient From my own POV I actually preferred the first letter but thats just my opinion. Maybe NOP will disagree but I personally felt this one was more needy sounding.
I have to say you have to really follow through with no longer wanting to go on in a marriage at your age with zero sex life.
My friend met her current partner whose wife said pretty much the same as yours. He had thought she might change but in 17 years (yes not a misprint 17 years) he had no sex life with his wife. He did leave a couple of times but the kids and home drew him back. He eventually met my friend and walked out for good.
Sadly this story doesn't have quite the happy ending for the guy as after a year she was on tamoxifen for breast cancer and SHE lost any interest. I'm working on her and telling her of how the guys here feel and she is hopefully going to listen and think of her partner. Her attitude is pretty much well I'm getting absolutely nothing from it so why should I. Pretty much like his wife's POV. When I pointed out but thats the main reason he left his wife for you she could kind of start to see HER behaviour was wrong. At least he had one good year LOL.
Seriously at your age kids or no kids I would rather walk than live like this and eventually you would be tempted to have an A yourself and can't say I'd blame you.
I realise now that my own H probably had his 1st A because our SL was pretty non existant. Unlike you my H did nothing around the house probably only made me 5 cups of tea our whole 31 years M and I was exhausted ,looking after 3 kids. My desire for him was pretty low because I really resented being treated like just the housekeeper. Had he treated me the way he did his 1st mistress I would have been way more inclined to ML. Guess he felt the mistress really thought he was wonderful and I KNEW all his faults as well as his good points.
Try to resolve this now or you will be unhappy for years. Lots of luck