You met someone new, you're starting to talk a lot with that person and you both feel an amazing connection and you have a lot in common.
You really feel amazing around each other.
You decide to have sex, and it feels great, you keep talking and you have sex a few more times.
After 3 months of this, that person even tells you that you're the one... that person wants to settle down with you.
The day after that, out of nowhere, that amazing someone just finds the most ridiculous excuse to get out of your life, and that's the end of it, sadly, there is no turning back.