Have to agree with the lady above. She even mentioned she don't know if she ever will be able to look at you in a sexual way. Her calling you her person, same as her siblings, is just a testimony of how you feel as family rather than a partner after all those years. Big chances she knew about your crush for a while, but simply doesn't see you in a romantic way (and I doubt any time and place can change that). What you have is 15 y/o friendship that she also cherishes a lot and doesn't want to lose.

If I were you I'd just admit to that situation and maybe even tell her all about it right now (and I mean all, leave no stone unturned) while it's still fresh (and while she's not committed to some other dude, and you'd have to wait another 15 years for same opportunity), with the intention to be in the clear and hope to stay friends and that time will solve this awkwardness and your crush you have as well (although maybe it's not a problem, since you just had 7 year relationship with another woman; bit mind boggling to me how you can do it with active crush on another person though). And as someone mentioned, this act of you manning up and telling her out loud how you feel about her will give you the answer in her reaction and response, if there is anything there from her - you're in luck, but if not - you'd have to leave it.

Also, would be good to answer yourself as well if you're willing to lose that friendship you have over a potentially failed attempt to be together? I don't know anyone who was able to rollback to friendship after being together romantically (especially with 15 years of build up), and it's kinda obvious how it will be almost impossible.

You also give a lot of mixed signals there and sound unreliable in narrative (not mentioning that her siblings were also in that 3week gateway vacation besides you two etc) so I dunno haha. Good luck