Something must have happened between CN and LB in April for DM to send that 'removing her from our lives' text message. I can't imagine he just fired that out of the blue unless CN just wouldn't let it go for months.
Not unlikely that she couldn't let it go. Also he had gone to Reno with her (CN) for a vacation late April to about May 5. It was May 5 he texted AM to keep an eye on LB. Perhaps CN had fueled his fire.