If it wasn't for page 6 it might even seem like she was giving birth to that curse. So he's a sudden Dragon Knight now and she's suddenly OP as well. That was pretty quick and easy. The world is basically his for the taking with her at his side.
There's 1 chapter left before the title and synopsis becomes spoilers for Volume 2. So I expect saintess should be appearing next chapter.
Page 11 and page 12 both have duplicate text. So I see neither the author, the artist, the protagonist or the scanlators are trying in this manga.