As the saying goes, if something seems too good to be true, it probably is.
Amanda's turbulent and abusive childhood forced her to set some clear boundaries for herself. She knew what she wanted and knew where to draw the line. But her boundaries were no match for Trevor's skillful and intentional manipulation campaign.
You'll be screaming "NO!" and "DON'T DO IT!" as you listen to Amanda's slow descent into the hell created by Trevor's immature, irresponsible, yet artful planning - then yelling "YOU GO GIRL!" when she realizes what's happening, pulls herself together, and becomes a better person.
Divorce sucks. But this is a case where divorce is clearly the best option.