Ugh, it's a long, drawn out story, but here's a rough outline.
She has major communication issues. She has major problems handling conflict. Between the two, she has a tendency to twist or manipulate her words. She means no malice, but it has resulted in some trust issues when she's been caught in an outright lie.
She wanted to go somewhere next month to do something with one of her kids and was going to stay at the house of someone she once fooled around with. Because of the trust issues she knows she's created, particularly with my husband, I was just shocked that she wouldn't consider that this would upset him. It upset me, too, but I doubt that there was a good reason she'd expect that...
We talked and for now, there's peace... we'll see how much she learned from this one.