Good boundaries around sex must also be made knowing that everyone has a right to privacy about the details of their intimacy. There's no hard and fast line that clearly separates one person's right to be informed from another's right to privacy; setting these boundaries requires compassion and negotiation. Certainly, you have the right to know about your partner's sexual activities with other people in general terms, but at the same time, the details of intimate acts are things that your partner and his partner can reasonably expect to keep to themselves if they don't want to share them.