Great conversation and good for you for letting it roll to voice mail after that. I would keep that up. Don't give her that power to play you any longer. It would be great for days on end if you could not talk and let her wonder what you were doing.
I would also let her know you aren't fine with her dating and tearing apart a family. At the point where the other spouse is filing for divorce is that the time to get tough and say what you really feel?