Can someone remind me how they are related again?

They're cousins.

But i kinda remember that the uke’s father had an affair and had him, and the seme is related to the first wife right? So basically they’re not related by blood right?

I don't remember if the same is related to the wife or the husband. I hope it's the wife so that the Uke and seme aren't blood related.

Yeah i hope that too but at the same time i hope the seme is related to the father so that the uke can get some money! Boy has been suffering for ever!