I know that this is going to be contrary to main-line thinking.
Please know that I prayed and thought about this for months before we got married. I just didn't listen.
Please, don't do what I did. I could have written your original post myself. I stayed in the marriage fo 18 years.
I wouldn't describe myself as the "worst kind of husband", however, I had to battle my way through extreme resentment, and daily heartache.
I strained at the gnat and swallowed the camel. And, that's exactly what I see you doing.
The gnat would have been to simply get out after the first month. At that point, my wife was still able-bodied, attractive, and could have found someone else more compatible.
I would have moved on, gone back to college, studied divinity and music, and become the minister I wanted to be.
Instead, she and I BOTH got to swallow the camel. Me, from an unmerciful financial hardship, and her, from a resentful husband doing his "duty".
this was a major mistake
Yes, it was. And, is, for BOTH of you.
The question, however, is what IMPACT you want the mistake to have on your lives.
If you get out now, you and your wife will, over time, forgive yourselves for the mistake and move on, while you are still young and can still accomplish what God has for you in life.
As you let this go longer, the impact becomes higher. God forbid that any children come into the picture, then you are REALLY STUCK.