A few bits I will add (feel free to subtract them if you disagree)
First, make sure that "enlarging down south" that you feel is not actually pent up frustration. Your W will detect that.
Be careful again about bringing up what YOU want. You just mentioned that in your last post. In my view, the purpose of this meeting for YOU needs to be to find out more about what your W wants.
I don't think you need to tell her what you want in a healthy relationship. If she asks, fine. Even when my W asked me a question, I usually gave a fairly short answer, then asked "what about you?"
In my opinion, you will need (at least at some point) to talk about the past. Most likely it will come up pretty naturally anyway, since you are separated. In my case, the best advice I can give is when talking about the past, affirm your W's feelings and don't get defensive. It will hurt to hear some of it again (and again), but it lets you know what some of the true sticking points are to HER.
Some things you'll think "wow! isn't she over that", or "I don't even remember that". But she does, and they seem very repetitive to her.
I personally would not ask the 5 year question. At this meeting, it will probably not include both of you.
Here's more along the lines of what happened with us. My W started talking about some job frustration. So I asked if she would rather be doing something else. That led into a pretty long conversation and some "what if's" started to surface.
Simply put, you don't need to talk about what you want very much. Only if it's part of the natural conversation, OR if it's a point the two of you easily AGREE on.
And, as I think about it, R/M talk is going to come in this conversation anyway. After all, that's what the post marital agreement is addressing.
I would think it WOULD be OK to affirm what she said several weeks ago. In HER view, is the post marital agreement something she wants in place so that it's done IF the two of you don't work out?
I wouldn't bring up ANY of the dating stuff for you or her. This meeting is about your M.
And, I agree with Ruined_No_More....with how you feel, don't say "yes, but....". That tells her you disregarded what she said.