I think you handled it well. As far as what to say if a similar talk happens again, I would just suggest that you do not go back over the fact of you not wanting a D and want to work on the M. She knows perfectly well where you stand. I think you should just kind of lean back and let her act out her little game, and maybe say very little......but enough to cause her to wonder if YOU could be changing your mind about her.
I don't understand why LBH'S think they must assure the WW that he is ready, available, and eager to save the M every time she brings up a R talk. She knows it already. And IMHO, he needs to stop telling her. For example, suppose you had not said anything about this not being what you wanted? Well, she'd probably say something trying to feel you out and may even say you must want a D too, since you weren't acting like you were trying to work things out. When a woman starts trying to put words in your mouth.....look out. It is a trap! Do not start arguing with her or try to convince of anything. Just play your best poker face the entire time she is ratteling off nonsense. Give very vague responses. I'm not that great at dialogs, but maybe this will give an idea of what I mean.
HER: You must want a divorce. YOU: Oh? HER: Yeah, b/c you don't act like you are trying to work on things. YOU: Maybe you have the right idea. HER: So it's true, you want a divorce?! YOU: I just know this situation is not working for me.
HER: Well, I'm scared and I just don't know if I would ever be able to trust you again. YOU: (silence) HER: I mean my anxiety level goes up just thinking about it. YOU: (silence) HER: Even if we D, we can still take time to work on ourselves and "tons of people S or D and end up back together". YOU: Not this guy. HER: If you feel that way then fine, I guess that is how it will be but I need to continue with the D.now. I need this time to work on myself" YOU: Maybe you are right.
You handle yourself with a ton of confidence. Do not act pitiful or sad. Just a strong, confident man who does need her in order to be happy.
Sure, she would storm off (after trying to get $$$), but she wasn't there to resolve anything anyway. But let me tell you, as soon as her temper cooled down, she would start wondering about you. You didn't preach to her, no repeated performances of how you didn't want a divorce, no pursuing, and you were not trying to talk her out of filing. This could be the first step in you becoming the guy she can't have so easily anymore. You become a challenge, and women love it. And of course, she'll have to temp check you again.
The thing is, most LBH'S are just too scared and will say, "But what if it just pushes her closer to filing"? Are you kidding me! She couldn't get any closer. She is playing with you, that's all. When she sees you aren't going to stand on your head and jump through hoops of fire, then she begins to see you as a "man" and not the pathetic H.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!