You say you don't think the kids would be happier if you separated. I would have been.
My parents were not happy together, they didn't argue much, and probably thought they were hiding their unhappiness, but there was this constant low lying tension in the air. Me and my brother knew, and we knew before we were 10 years old.
They did eventually divorce, when me and brother were adults. However my mum died at 55, and I do feel a lot of guilt that she spent more than a quarter of her life miserable, supposedly for my sake.
I've been with my partner 16 years. We have kids together, but we're not married, each for our own reasons. But in my case it's because what was modelled to me as marriage growing up was all kinds of crap.
Your relationship doesn't work, it started for the wrong reasons, and has completely the wrong power dynamic, which has unsurprisingly given you the ick.
End it. It'll be fairer to you, fairer to your husband, and fairer and healthier for your kids.