Tbf in later chapters it revealed him went total crazy in 1st timeline was due to external factor. Dunno if you still read it or dropped it but the external factor is ................................................ he was drugged that ruined his health and his mind then manipulated by villains to ged rid of fl, even fl also drugged by the villains in 1st timeline. Well 1st timeline was simply chaos. Iirc fl also once mentioned he wasn't violent at all in the beginning despite their cold marriage and in 2nd timeline it proven he still not violent, just arrogant at most. So while it's really frustating for us readers, she does have good reason to forgive him.
I was on chap 35 when i was like “this is suspicious why is mf thinking about forgiving the ahhhole?” Then i check comments and omfg i was right. This fl is seriously braindead. Even if the ml is not he same as the old ml mf he r/ped you and throw you into the grave at the same time AND YOU STILL WANT TO BE WITH HIM???