I need to hear some advice of how to handle this that is draining my energy and affecting my mental peace. I have a best friend, let's call her Jane. Jane and I have been friends for over 6 years. She is a wonderful girl, full of life and sweet. She helped me many times in my relationships and life in general always being there for me. I try to do always the same for her, being on her side no matter what happens and I promise her to be there for her. Sadly, in the past months, her romantic life has been one of the worst I ever faced in my life.
For context, around 6 years ago (the same time I met her) she was dating this guy (let's call him G) that it's the typical story of an intense, toxic relationship. He cheated on her, was abusive and assaulted her many times. Once they broke up, he assaulted her one more time resulting in a pregnancy and She decided to interrupt it. Was one of the most traumatic experience she ever had in her life. After it, she tried 0 contact with him. Despite all the hell he made her pass through, she will sometimes mention how much she loved her and that he was the only man that made her feel "safe" and "happy". She tried to move on, having other relationships, sadly, she cheated on her next boyfriend with G, making the stuff even worst. She promised that she will stay away from him, but finally Jane gave up, and restarted contact with him. Currently, G it's married, but he is saying to Jane that doesn't love his wife and it's looking for a divorce just to be with her. It's been like this 4 months already, and Jane is passing again through a Rollercoaster of feelings. To make things more complex, I got Jane a job in the company where I work. I'm her direct supervisor, the last year she was excelling and being my best worker. Now, she barely works, takes long brakes to call G and gets late or doesn't shows up to her shifts. She is starting to affect me work wise and I don't know for how long I'm gonna be able to cover her before my supervisor catches her.
And now, the cherry on the cake, Jane is again pregnant by G. Now she is having panic attacks every single day and loosing her mind.

All this time I have been on her side, supporting her, calling her and make her understand that G is a monster and he is manipulating her just to take advantage on her. Despite all my efforts, she is still "in love with him". 2 days ago I was fed up and exploded towards her, telling Jane that I can't do this anymore and that I'm ready to finish this friendship if she is not willing to change and listen, not only to me, to her other friends as well. Of course I'm not gonna stop helping her, it was the heat of the moment, but I'm reaching a point where I can't bear seeing a person that I truly love destroying her life and dumping all her dreams and hopes by a guy who is clearly abusing her. And for my, the worst part is Jane not willing to listen or accept help.

I need someone to tell me how to deal with this. I know I can't force her, it's her life, she made those choices, nobody forced her. But is starting to affect me deeply, even work wise. I need to find strength again to keep helping her. But something it's sure, seeing her pregnant is gonna break my heart, I can feel it. She always dreamt with a family, to have a husband that take cares of her and having children. I want her to chase that dream, but it looks almost impossible...