"She told me that this is who she is,"

Besides telling you, she's demonstrated time and time again who she is, so why won't you believe her???

In all honesty, your wife sounds like a miserable Fuck. Call it depression or whatever, she is incredibly unhappy. She probably doesn't have the slightest clue how to be happy.

Unfortunately, there is very little you can do to change her. The desire to be different is something that has to come from within her.

If there is be any chance of salvaging to your marriage, you need marriage counseling ASAP. Your wife likely also needs individual counseling, and possibly medication.

Stand your ground, do not procreate with this woman. You think life is hard now, just wait till the Postpartum Depression kicks.