Instincts are what was driving him to want to impregnate Doyun, not love. That is the whole purpose of ruts and heats or he would have been trying to do that during regular sex and he would have said he loved him when his head was clear.
Can we just be happy they will likely be dating officially soon?
It is not confirmed in the current chapter.
spoiler
It becomes official in chapter 36 when doyun asks taehan and taehan actually cries bc he is so happy. Then doyun is like I'm gonna tease you (about crying) forever which in itself is the cutest confession and so appropriately made given their personalties. I'm saying this per dream and nike's translations .

WELL HE KNOTTED HIIIIIM! HE LOVES HIM SO MUUUCH HE WANTS TO BEAR HIM HIS BABY (: GOODLUUUCK I HOPE THINGS GO WELL!