Find a compromise
When your parents get a little too involved in your life, enforcing your boundaries can remind them that you can make your own decisions.
After reinstating your boundaries, you can also meet them in the middle by offering a compromise.
A perfect way is to let out some information. While you don’t want to talk about your sex life, you may be fine with answering nonsexual questions about your dates. Discussing the details you are willing to share and skipping the ones you aren’t can help them feel more included without compromising that boundary.
If you are not sure what to offer, you can ask what they are looking for. Collaborating to find a solution can leave you both satisfied while allowing you to maintain your boundary.