Momentary setback, Grizz. Push through it. You're doing well. The next day will be better. Your wife is dealing with her own frustrations and she has good days and bad just like you. Give her room to fluctuate.
I don't think any of us will ever reach a point where we are fully detached. I think that's just something that happens when you love someone. Can you imagine ever reaching a point where nothing in your daughters' lives could ever affect you? You love them, always will, and will never fully detach from them because of that.