Summary

It's basically about A found out that his bf,B cheated on him with A's brother,C. C also frame A that A killed their grandfather and A got into jail. A slept with D in jail the day before he got out of jail and were pregnant with D's son and they met again after 4 years(?)

I think it's 2, but yes, great summary. It's basically about A's revenge against B and C for the framing incident that ruined A's life. Sprinkle in some cute family moments between A and D and you've basically got the whole plot.

Lol same, but you easily get it once you start reading.

MC caught the boyfriend and younger brother together in bed one day, and later on gets framed by the younger brother for the death of his beloved grandfather. Spends like 5 years in jail, that's where he met the ML, except after their one night stand, his release date is the following day so he runs away. 2 years later, he has a child and also planning his revenge when he meets the ML again (ml has been looking for him since thst night but got given the wrong name so eh)