I would be very blunt about this fiction. It's interesting and good all said but Mc is a trash. He is supposedly million years old and
has a god like mindset, which I see none in him. Secondly, he whines like a child, and acts submissive in front of Riveria. I get it you wanna make a Mc that doesn't acts like he his on high, but realize what the heck you have made. You say he sees her as wife so he acts like that, but actually that's totally wrong. They aren't hudband and wife and secondly making romance so slow, not to mention. Riveria blames him for everything, like it's his kistake they aren't getting members, etc. In the end he have become a outlet for her frustration, the character development and world background both suck. Otherwise it's good, and well since the main part of it sucks anyway, I don't know what you should expect.
You can try to make a rewrite considering you have a very low number of chaps.
You will need to plan for the lore, plot and things more. Lastly, you gotta focus on Mc's personality.
He should have been a bit of aloof, cold yet kind personality as a God of light. Riveria should have developed a crush on him, and he as well. That's how romance have progressed.
I will be blunt, this isn't quite good. but you can try to make it better for your future readers. Anyway I will be leaving.
-Akros peace out...