Husband takes mistress home to sleep in my bed, will it affect Feng Shui?

It has nothing to do with feng shui, but it is directly related to your psychology. I think for such a bed, it will definitely stimulate you to often think of the scene of them together, which is the most tormenting feeling. If this matter is not over yet, you may clash with him at any time because of the thought of this scene, and you will also make yourself extremely uneasy.