There's a slight difference.
Makoto only has a part of Hotaru 1's soul inside him.
Most of Hotaru 1's soul was used up and gone in order to grant her wish. That's right. Inside Hotaru 2 is a demon.
The demon became human in Hotaru 1's place in order to grant her wish.
Later, at the end of the story, Makoto is on the verge of disappearing because he has so little soul left. So that Hotaru won't be alone, the two decide to have a child. That child is Mina.
The two get married soon after graduating from high school.
Makoto doesn't disappear easily.
It's only a little later that the two learn that a soul that has mated with a demon is trapped by it forever lol