How to accept an ending you didn’t choose and be alone now?

I’m a 30 y/o female. Had the proposal, wedding date + vendors booked… he ended the relationship 6 months before the wedding saying he fell out of love (he was really mean at the end too which was so shocking since he was there for me during the relationship ship, and disclosed former cheating/kissing) the wedding date recently passed and it’s been hard…

I THINK WHY COULDNT IT HAVE BEEN GOOD?! Are there things I could’ve done to change the outcome…