I've been where you are now. Your wife is the same age as mine; I have two kids.
I've tried everything to make my M work since the Bomb. Got in great shape (running 5ks now), did a lot of inner soul searching and changed a lot of my behaviours. Restarted a lot of hobbies as well as aiming for a new, rewarding career. Did a ton of 180s, and made a huge dent in our family debt.
Guess what it's gotten me?
Nothing.
Just some more stress, some time with my kids that I'd have missed out on.
A wife who says she'd leave me if it weren't for our kids, but she'll "do anything" to make me stay. But she won't say "I want you to stay." Has no attraction to me.
Read my boring sitch. We all think our sitchs are special snowflakes. They're not. Most are extremely similar if not identical.
I wish I had done things differently after discovering this site. Instead, I picked and chose from the advice for stuff that I liked, that reinforced my beliefs. Well guess what, my beliefs were wrong.
I should have said "You want your space? Go ahead, move out." Barring that, I should have said I'm moving out.
I've wasted four months, and possibly ruined any chance at salvaging my marriage. But for me, I know what didn't work: trying to be her friend; trying to be nice; trying to hold/cling to her when she didn't want it.
Now I'm belatedly moving out because I don't want to live with someone who's willing to trade sex for financial security. When I type it out like that, I realize how screwed up it is!
Learn from other poster's mistakes.
A good post to read is Gucci's "Setting them free."
