There is no way Ron went to Nicole's "just to return glasses".
I don't believe a young 25 year old man was going over to Nicole's at around 10:30pm at night "just to return glasses". He could've returned them at a later date during daylight hours when it's more appropriate.
Not to mention, Nicole had on that sexy black dress and had the hot tub running with candles lit. It was obvious what she and Ron had in mind.