Should I tell my FWB I practice witchcraft?

You don’t have to present it as a confession or ask for approval. If you want to be more open with him, you could say plainly that you practice witchcraft and that you understand he may feel differently about it. Then let him decide how he wants to respond. If you think he might react in a way that puts you at risk, choose a safer setting or don’t have the conversation alone.

There isn’t one automatic disclosure rule for every casual arrangement. But if keeping this private makes you feel like you can’t be yourself around him, that’s useful information about whether this setup works for you. You could tell him because you want honesty, not because you need to persuade him or soften the word for his comfort.

The part about hoping he might distance himself stands out. If you want this to end, you can end it directly instead of relying on a disclosure to make him leave. And if the real issue is that he has hurt you emotionally, you can name that boundary separately. Telling him about your practice and deciding whether to keep seeing him don’t have to be the same conversation.