For people still not over their ex

So i've been on a few dates the last months and twice now (to my memory) i've had girls tell me they're not over their ex. 1st time was during the date which was quite a shock as no indication of this was given before and the 2nd just happened after going on two nice dates only to get two weeks of ghosting and then being told "we're giving it another shot". It's pretty disheartening especially with the second as i felt real relationship potential and i was kept waiting for two weeks wondering what was going on.

I guess my question is how obvious is it to people who've been on the other side of me, did you already know you weren't over your ex? Did it take going on a date to fully realise? This is also a bit of a vent post as it sucks to be on the receiving end of this, being ready to let someone in for them to abruptly leave after putting their foot in the door. Ultimately i want people to be happy and be with the people they need to be but it's rough out here being the pedestal you use to figure out things.