My family already knew my ex-girlfriend before we started dating, so it wasn't awkward in any way.
My ex-girlfriends mother and father? The mother hated my guts, probably because she is VERY religious and when I was introduced, she put holy water on me (she has a fountain of it in her hallway) and I grabbed my face screaming "IT BURNS" My cousin (who was present with us at the time) and my girlfriend laughed, the mom was...not amused.
The dad, who is also heavily religious, was not there when that...scene occurred, but he was alright, he didn't approve of his daughter dating, but knew it was something teens do, he didn't like how I was an atheist but ultimately respected my right to not believe in god, so he tolerated me and was an okay chap, he did tell me that if I ever slept with his daughter before marriage, he would end me and I believed him, he was an intimidating dude as well. Me and my ex did have sex and I don't think he ever knew about it, considering I am not 6 feet under right now.