The things you learn on TMF...

1) I'm very worried about whether or not she can handle us breaking up
I am, too, because with your footprints all over her back, her horizon must seem very limited.

2) I really love her and hate that she did this – I don't know if I can trust her again and I told her many many times that if she lied to me again it would be over.

This is complex. We'll have to break it into parts:

"I really love her."
Well, that's patently false, unless by "love" you mean "I really enjoy trying more and more outrageous attempts at control and having them succeed."

"I don't know if I can trust her again..."
Not in a state with a concealed-carry law, certainly.

"I told her many many times that if she lied to me again it would be over."
Another mistake on your part, I'm afraid. It was over pretty much when you, one of the partners in an allegedly loving relationship, confused your role in that relationship with that of the chairman of the Taliban, issuing a fatwa.

3) Jeas, we have a lot to lose.
Good point. She's clearly in danger of losing her self-respect, in much the same way that some time ago you lost your grip. And your ability to spell "geeze."

"I don't know how much money we'll lose trying to sell our house this early, etc."
Whenever a close, emotionally satisfying relationship has begun to turn bad for me, I know the first thing I worry about is the equity.

4) If she lies about something small, what says she won't lie about something big.
Like, saying she loves you.

5) I can't figure out a way that she could convince me this won't happen again but one of the things she kept saying last night is “I've worked hard to not lie again…”

You could try asking once a day "Have you stopped lying yet?" That's about as close as I can come to "Have you stopped beating your wife?" in a quick reply. As for her working hard to not lie again, maybe she wondered what you'd start in on after so maturely shoveling the contents of the bathroom counter into the sink.

Have you considered holding your breath till you turn blue? Or, even better, until hypoxia settles in?

6) The times that I have caught her lying she denied and made up more lies – not just admitting to it, until I totally proved that she was lying before she admitted it.

Look, take it like a man. She's not worthy. Don't waste your time on her. Get your own place. You'll be rid of her and better able to concentrate on a prize-winning costume for your pet ferret to wear at the next Star Wars convention.

7) If I don't break up with her, after promising her that it would be over if she lied again, what will that tell her?
That you're an inconsistent small-minded control freak.

8) Are there any totally honest females out there?
Yes, but those who know you have been restrained in their reaction because they're unsure how far "justifiable homicide" extends.

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As for the rational people on this board:
Doesn't TarBabyAlert ever drop by here?