First: Set the bar right off the top.
Let he/she know where your romantic future stands!
This is sometimes the most uncomfortable thing ever. Someone that you would never romantically be interested in is the best business affiliate ever. Or it could be someone that you are largely attracted to but know romantically being involved will complicate “The Business “.
Whatever the case SET THE BAR.
Let he/she know in the first uncomfortable interaction what will or will not be tolerated.
This will give your associate a strong idea of how to interact with you going forward.
If you have to think about your stance being taken the “wrong” way or losing an income opportunity I would strongly suggest that this was not the best work relationship to begin with.
Next. Be professional!
Always always put the business before any personal anything. Casual introductions are fine like How was your night? Or, How are you? But the very next topic should be swayed toward the business at hand.
For example I managed a modeling program back in 2016, one of the models did not show so my business affiliates and I made the decision for me to fill in.. The model’s attire for the night was a little more proactive than usual while working this type of event for me but I still had A LOT of business to handle at this particular event. So whenever I was complimented in an overly flirtatious way I would counter with Thank you, Do you know where the photographer set up is, or Could you brief security on how to handle the model prospects?
So immediately after someone flirts, change the subject to The business at hand.
You can be gracious or brash; the only thing that matters is that you remain professional!
Lastly. Manage your Emotions.
Business is Personal.