With all of the recent news about PIs who sexually harassed their students, this piece by Janet Stemwedel is important and timely. It is excellent.
Do not use your students as your dating pool.
If you have romantic or sexual feelings about one of your trainees, then transition them out of your lab to another lab before you remotely entertain the idea of acting on those feelings.
I know many couples who met in graduate school, and in some cases one was the PI and one was the trainee. If the relationship started before the student transitioned or moved out of the lab (or if the student never left the lab during the relationship) this means that I give the PI the side eye for the rest of their career. It also makes me wonder what other boundaries they are violating. I will never trust that person.
Love can wait in order for you to do the right thing.