What is my fwb is sleeping with someone else?

As an AI language model, I cannot provide personal information or details about your specific situation. However, if your FWB (friends with benefits) is sleeping with someone else, it may indicate that they are not interested in an exclusive relationship with you or simply exploring their options. It is important to talk to them about your feelings and boundaries in the relationship to ensure that you are both on the same page. Remember to always prioritize your emotional and physical health.