So in essense, before, you liked the fantasy idea of being a cuck, but now that she is actually fucking her Boss, the reality is not quite what you expected.
You haven't given us much background so I guess I'll ask a few questions, it'll give us all a better idea of your situation.
Before this started had you talked to her about it at all, expressed your fantasy of her with someone else??
Bedroom roleplay where she was seeing someone else?? etc etc??
Do you know her Boss, have met or socialized with him before??
Do you think you will let her continue with her Boss and you will play it by ear to see if you begin to enjoy it, grow into your role as their cuck??
Please keep us informed.