Honestly, the story is kind of gross.
Below, there be spoilers...
I'm not even talking about the age gap when I say it's gross, though I do take offense to the author having them consummate their marriage in the new timeline when she's 17, and he's a 30 year old man. If author really wanted that to happen quickly, then have her "vision" happen when she's 17, not 16. And yeah, it's not even a regression story, she has a vision of the future, so she really is a 17 year old, not someone older stuck in a 17 year old body, and ends up sleeping with a 30 year old man.
With stories like this, I'd prefer for the FL to have more time to mature, so I'm usually not even okay with sex at 18, maybe some separation and/ or a time skip so she's in her early 20s, but at minimum I wish it would be 18 years.
But that's beside the point. This girl gets married off to a grown ass man at 7 (9 in the manhwa, so hopefully they'll have the consummate age be 18+) and it's not like no one knows this, but everyone gives this poor young girl, who found herself in a situation she was too young to understand, such a hard time. The story starts when she's around 16, but she's obviously been treated terribly for a long time. I understand the ML distancing himself because he doesn't understand what to do, either, but I wish he'd made some effort to get through to her earlier. I also wish she wasn't cut off from her family the way she was. I've read at least one other story where an older ML marries a child bride for reasons, but they were at least on friendly terms, he didn't ignore her, and she wasn't isolated. Also nothing romantic happens before she's of age (and I think there was some distance between them when she went through puberty). It was years back so I didn't remember it as much, but child bride and adult husband stories CAN be done right without making it gross.