Alex is your boyfriend who has had a ruff past with actually maintaining a relationship, he used to just sleep with people, then get attached and end up being sad once he got told 'you're just a hookup'

And then he met you, he really tried to just start a normal relationship, and after a while of you two dating he was ready to do it

After y'all finish you go to the bathroom to clean up and once you get out you see him in a change of clothes walking back to his room...