STAY THE COURSE, Bart. It's working, and DB's main mantra is "Do What Works!"
The key is in your TONE, your DEMEANOR. Don't BE a "hardass" if that's what you were before. You want to go for a "gosh, this hurts me more than it hurts you, but I need to protect myself here . . . I wish this was going differently, I really do" sort of a feel (not those WORDS, but a FEEL). Does that make sense?
When my wife went into her "St. Sally" routine (not her real name) and tried to push her A underground, I used a lot of "Gee, I wish I could believe that right now, I really do"s with her. I wasn't a d*kk about it, but I made it clear that her lying had made me need to protect my heart, and our family, and that I just didn't believe her right now.