Sarah, is this a pattern that has been consistent from one man to another for you? Or is it a new thing?

I do not think that you need to ask him because he's already answered. The culprit here is not the guy but your sis, right? Why does your sister think that it is her job to spy on his FB contacts and convey her intelligence to you? You deactivated FB so you must have had a reason to do so, but then you should not be accepting FB-based intelligence from your sis.