My sister's boyfriend cheated on her with numerous women and she is not able to break up because she loves him so much. What should I do?

Face reality.. There is a serous shortage of men of all ages willing to get with women anymore. This guy is in the minority of men and there are a lot of women out there looking for men. Supply and demand.
Since he willing to risk it all being involved with women he's in a false utopia world hence he's living in delusion. Sooner of later he's going to let one slip past the goalie (get a woman or women pregnant) and then his whole dilutional utopia world will come crashing down and that the "happy ending" the worst one is being falsely accused of physical abuse to rape. Today one or all of the negative outcome with women is inevitable.
I say let her have her intoxicating drama over this guy because when it ends there is a low chance of getting another guy to get more drama fixes after him.
My sister is pregnant and he doesn't give a damn
But my sis says he cares about her and he loves her but just yesterday she fought with him because he was with another girl in his bed
She kept on defending him and got a bit angry when i told her she deserved better
I would have her really cut it off because this is a damaging relationship from the looks of it.
How should i do that? Because she gets offended when i told her to cut him off she doesn't listen to me
I tried that many times but she showed no interest , she broke up with him many times before (she used to listen to me before) but after somedays she ran back to him inspite of me warning her again and again
Opinion
1Opinion
She's likely desp. and doesn't think she can get any other man
She is beautiful and hot she has a lot of men who like her
But I don't know why she is like that. She told me she loved him so much and she would not be able to love anyone like that again
Like i said, she is likely DESP. and doesn't think she can get any other guy. she's dealing with self confidence issues, no matter how many guys are after her
Superb Opinion