Hi Fraser,
Welcome to the family. You ask a pointed question: "Am I being taken for a fool?" None of us can really say, but let me take this from another angle - about ending and starting relationships.
If I was in your shoes I would just focus on your choices. You decided to leave your relationship. That's fair. Are you in the process of getting a divorce? Or just separated? Until you get that cleared up you bringing another person into your romantic life is gonna be hard and not fair. I am 7 years into a relationship with someone who I thought was divorced and his past settled when I met him. Instead, it is 7 years later and he is still fighting with her in court so that is where I am coming from on this. I can say directly that had I known I'd have to go through
his divorce (he had to divorce her again by another country's laws a year or two after we met!) I like to think I would have not started this relationship at that time and just focused on my life. I've had great times, but I've also had horrible ones because of those issues.
His divorce had to be resettled/redone according to a 2nd country's laws - and the kids and custody stuff too, lots and lots of drama I didn't want/anticipate entirely, but my heart was attached and I thought I could handle anything. (I also didn't know he had BPD traits.) If I could do it over, I would have rather not started together so soon. It is not all his fault, he genuinely thought it was settled before we met, but her moving countries, etc. affected the process and dragged it out. And we were so excited we plunged forward thinking we'd be able to handle it all. But it was too much and it may have left such a stain on our relationship we might not make it in the long run. By starting too soon, and going through too much, we've burned through a lot of our good will and some of the fun/easy times we all deserve, in my book, at the start of a relationship.
And on the other side of things... .her? Well, she is not done with him in all likelihood as much as she is attracted to you. She needs to resolve that before you can start clean and clear. She is going on holiday with him why? Because he doesn't know and she isn't ready to leave him it sounds like possibly. She probably has a lot to sort out with him and what if he fights to keep her? It is hard and it hurts, but I would highly recommend you slow down and wait. You will likely do a lot of waiting for her while she sorts that stuff out. Are you prepared to wait? Or do you want a
triangle because that is what you'll have in all honesty. (This link on triangles is something to consider:
https://bpdfamily.com/content/karpman-drama-triangle)
The more you mix this stuff up now, you leaving and her leaving, and her having trouble getting things sorted with him, will just bring you trouble and heartache. This is not how healthy relationships start in my book at least.
I know that is not what you wanna hear in the heat of the moment. I understand passion!

I had a chance to run off after someone once. That guy was amazing, incredible, and I can barely deal with realizing I missed out on him not once, but twice in my life, but I... .it would have been a mess at that point to "get together" and I am sure it would not have lasted more than two years before the passion no longer outweighed the fact I'd be selling things short for myself in life and would find myself ending another relationship that probably
could have been great if we could do it the right way - two totally free people with distance between the past relationship and starting new. I might have had two exciting years, but then what? How wrecked would I be by then if that was the best I could do with that?
Anyway, I would not give her an ultimatum, but I would set a personal amount of time I was willing to wait for her. You are ready to meet a new woman, so if it is not "Vicky" it will be someone else at some point. There are many wonderful people to meet and you can find love in the most unexpected places.
Yes, it just happened because you were both vulnerable. I so get that! But it will also be an uphill climb until you are both free and clear. Be patient. If this can work it will, but I am serious man, don't jump in so fast to something new or you will burn it out. This shooting star will burn to dust. Just my two cents.
Wish you the best and hope you don't mind me bringing myself so much into this reply! Thanks for the chance to let me put that stuff into words. It's been eating me. I don't want you to end up hurt and this scenario is just flashing with potential hurt for you!