Hello, looking for another one shot:

So MC gets dumped by his boyfriend and doesn't know why. When he gets home a stranger (Str) is there who refuses to tell him who he is, just says he's from a star (?) or something. Eventually, MC gets used to Str and starts to look forward to him coming over and wants to know more about him. They have sex and it's revealed that Str is the brother of MC's bf and he tricked his bro into thinking MC was cheating on him (when in reality MC was working hard to afford dates and gifts for bf) which is why they broke up. Str wanted MC for himself.

Thank you.