How to See This Man at Work and Act Normal

We've shared everything together and other than the obvious because we are a secret and wanting kids. There's never been any problems. He told me he signed up to Bumble and took a spontaneous trip away with a girl him at the day prior and enjoys her company. How do I see this man at work and act normal? How do I let go when nothing bad happened to turn me off him?How do I turn off this intense almost rage feeling at the thought of him with another woman?I literally feel like I have died even though I have so many other things in my life that do make me happy. But I've lost the person I love so much. Probably just lost my