Cheating boyfriend

So I’m posting a friends situation, not mine. Just want to hear other people’s thoughts.

So my friend and her bf have been together for 10 years. They have a 3-4 year old son together.

He never helps with his son. He constantly refers to him as her kid, and whines every time he has to watch him for 5 minutes and says he’s too much to handle. He spends his nights at the bars, and never spends any time with my friend. He blows their money and never acts he wants anything to do with her. Lately (the last 6 months) he’s been spending the increasing amounts of his time with a pretty little 22 year old woman (this guy is 40 something). My friend has voiced that she is uncomfortable with him spending whole days ALONE with this girl, but he acts like he’s doing nothing wrong and expects her to apologize for being “insecure.” She has no problem with him having female friends, but the fact that they’re together pretty much 24/7 and a lot of the time they’re alone makes her super uncomfortable. This last one he was spending time alone with her last night in their house at like midnight, playing loud music and stuff. She texted him saying she was uncomfortable with it and asked him to please ask her to leave soon, especially since she had to be up for work at 5 am. Today he expects an apology from her. She has no idea what to tell him.

She talks about leaving him, and personally I would have left by now. It’s obvious he’s having at least an emotional affair. But she thinks about her son and their house and how complicated it would be to leave and she hasn’t done it yet.