Will You Go Back To An Ex That Slept With Your Friend?

I was chilling with a friend this evening and we got talking about a mutual friend of ours who supposedly slept with her ex boyfriend. She actually caught the lady in her ex's house so it was not a hearsay or something.
She left them in the house with hot tears pouring down her cheeks. This guy(her ex) tried to apologize after some days but she was too hurt and she told him off. I couldn't really do much 'cos it was her decision to make whether or not to continue with the guy as it was a very delicate situation.

Fast forward to some weeks later, the mutual friend started flaunting the guy on her social medias, putting up pictures of both of 'em in intimate positions and different outings. My friend couldn't take it anymore and she had to delete both of them from her list.

It's been three months plus now, she has moved on, she's not seeing anyone else but she's doing good. All of a sudden, the guy wants her back! According to her, he's been begging her for over a week saying it was the devil and all...

I told her frankly that if I were in her shoes, I'll not even consider it but I don't wana shove it down her throat. My fear is that this guy might just take her for granted again. This is a relationship that lasted well over two years before they broke up.

What's your opinion? Do you think it's gonna be wise for her to go back?