How to deal with a cheating friend?

My friend (23F) recently confided in me that she cheated on her boyfriend (22M) with their coworker (31M) who is also in a relationship. This happened drunkenly at a work training where her boyfriend was not there (they all work for the same company). To make matters worse she got pregnant and decided to have an abortion. She said she told the coworker who was supportive of the decision but she went through the process alone and only told me a month after. While I think she recognizes the gravity of the situation and is incredibly remorseful, she is having a hard time dealing with it all. I am disappointed and mad for what she has done to her current boyfriend (who I am friends with and still doesn’t know). At the same time I can’t bring myself to out her knowing she is already in a dark place and I feel in some ways she was taken advantage of. Basically I don’t know how to support her while resenting her decision and the position she put me in. It sounds like the coworker still checks on her occasionally and is trying to be supportive due to the situation he put her in but it makes me feel even worse not telling he boyfriend knowing they (friend and coworker) are still talking. What to I do?