The girl wasn't a mistress. She was Mr Xia's ex girlfriend who was still in love with him. Lucky wasn't his wife, although Mr Xia was pursuing her because he wanted her to be his girlfriend
A simple solution....make the mistress and any other woman that wants to get their hands on her husband, boyfriend or fiancee know that they don't stand a chance.
What doesn't make sense is that this actor almost allways get this really nisched carachter. That makes it hard to like him cause I allways see his carachter be this bad. Really needs to get other roles before it gets to be a problem for him.