I went back and read your first post and you indicated she wanted space and it sounds like your putting on the full court press. Her actions with the coworker are definitely inappropriate. The way to go here is in the opposite direction and see if she will pursue you. She can’t be connected to you while she has this connection with the other guy. Odds are you are just seeing the tip of the iceberg and 95% of what’s going on is on the down low.
Right now you are plan B. How do you become plan A?