After the Passerby Lost Her Husband, She Was Forced into Marriage by the Protagonist

Here's a summary: The protagonist meets his background lover but discovers that he already has a family. He tries his best to be the mistress and has sex with his ex-husband but never succeeds. Then he discovers the story of winning a jackpot, his love rival burping, his lover losing his memory, and he is gearing up to take over. (I want to write some ruthless drama, but I recently fell in love with the mistress...) Purpose: Love must be correct and firm