I'm sure that in some world that is fair!
I think it was just wishful thinking that took over, causing OP to lose the ability to do math. Divorce is a hard thing to go through, and it takes some time for reality to hit. Then you have to realize that things are going to really suck on one income. My xh and I made the same salary and I had to get into debt before I realized that I had not made enough lifestyle adjustments. Live and learn (and pay the price for your mistakes)!
OP is lucky actually... $100K of husband's inheritance helped buy that house and probably allowed them to have a much better house than they would have without it, and she still gets half the equity. Not a bad deal!