So to begin with I've been with my OH for 20 years we have 2 teenage children and other than usual relationship groans we are happy. About a year ago a new guy started working in my office and we hit it off straight away as friends we have a lot in common we are both gym fanatics so we share tips and stories about that plus his children are similar ages to mine and he's been married for 15 years and appears to be happily married. We just get on have great banter and have similar backgrounds.
Anyway we have become great work friends, as I don't drive he regularly offers me lifts home which I accept, we both meal prep and share food alot. No lines have ever been crossed, we have each other's numbers but have never used them, when we are alone nothing innapropriate is ever said if anything he asks for my advice on gifts for his wife and we share stories on the latest shenanigans our teenagers have been upto. Anyway my best friend who also works in the office has recently asked me out right if we are having an affair and when i told her 100% we are not she is now convinced he has a motive and I am being Naive into thinking he doesn't want more. She claims to have seen looks he gives me and has pointed out some "jokes" he's made recently, e.g. he called me his "work wife" as I was nagging him and then last week we was going out at lunch to pick up some food and he made a comment that we was "going on a date". She also continues to say his wife wouldn't be comfortable with our friendship.
Anyway until my friend highlighted this to me I felt perfectly comfortable with my friendship but now I'm worried have I crossed a line without realising? Am I being Naive into thinking that a man and woman can just be friends?