From the comments under the novel, I see that many people kind of found the fl irritating cuz she was overly territorial over him and was mean to all female characters. Also they kept saying the fl is drastically different than the one we saw in the first few chapters and did not behave like a saintess at all. Also the ml takes way too long to realise its love he feels for the fl and not just loyalty. All in all they do end up together and have kids.

Not many spoilers available
But one I read is ,
it is the FL who keeps turning back the time each time to save the ML
It is the reason she is blind. She turned back the time 100s of times at the cost of her eyes.