Ten Dates

I did this after my initial playthrough, as the game will let you speed through. There's several different ways to go about this, starting from the main menu here's what I did:

Select New Game
Select Misha
Fill out your bio however you want, just click through it

Press to skip already seen cutscenes

The game will now let you select your speed dates
Select Ty (and only him)
Select Start

Select "Ask"
Select "Not cool"

And just like that, we're done with Ty - a mystery suitor will now appear
Select "No"
Select "Accept"

Achievement will unlock after the cutscene.