Should I end it?

So I (25M) was on hinge and other apps for about an year, went on 7-8 dates in all, some things, sometimes i got ghosted, sometimes things fell apart. It was looking pretty bleak, but around july i staeted talking to someone and well we were talking pretty slow, like a reply a day (reply consisted of 6-7 messages on each side mostly). But then i matched someone towards the end of july(Lets call her Stacy, idk), and i was on the verge of deleting the app already coz i was done with dating apps. I shit you not, this turned out to be THE BEST talking stage ive ever had, we chatted about anything and everything, stupid things and life. Flirted back and forth, she told me at a point that "I tick a lot of checkboxes", we went on a short date, texted afterwards. Both said it was nice and all. This went on for a month.

The next day i texted her that if she is up for another we can plan something in some time. To which she said she would like to stay friends right jow, which i guess was a END IT sign but i decided to stay because again, I had never ever vibed with someone this much (i was also talking to the other girl here and there because she was quite nice to talk to too but it wasnt really moving anywhere). I had deleted all the apps by this point because I tried talking to some people and it didnt click like this girl did( i swear i felt i needed someone like that only) Post that discussion everything changed, replies started coming in late, no more texting all day, flirting stopped.

So i decided to tell Stacy my feelings and end it, which well it did.(This was about a week ago) Now ive been talking to the first girl since and its going very nicely, but i still keep thinking about that one girl.

Am i wrong for this? How do i stop thinking about someone who let go so easily? Is it wrong to talk to this girl so much while i sometimes think about Stacy out of nowhere(i swear i wanna forget because well I dont wanna ruin myself over someone who does not like me once again which has happened very long ago once before) Any advice?

Edit 1: I have gone out with the second girl on a date, and she has told me that she likes (i have as well), but having stacy on my mind still feels wrong.