Thanks for your question and that's certainly a tricky situation.
While we cannot give specific workplace advice, we can provide best practices and in a situation such as the one you describe, a best practice would be to make their working and romantic relationships completely transparent (and documented) with a written summary indicating how any of the parties (producer, direct report or employer) will modify the situation if/when any of the parties no longer feels comfortable in that situation. In other words, outline (in advance) how you will unravel the situation when it turns problematic and put that outline in writing and agreed to by all parties.
Hope that helps.
Workplace & Harassment Expert
March 6 2018