It's natural to be tempted by someone that's attractive and shares a common interest with you.
I've only acquired two female friends in 25 years since I graduated college, we are all coaches on the same HS team. I got a little thing for each of them, but we are all happily married and I would never act on it.
Question for LRC: Hypothetically, if one of their husbands and my wife were both killed in a horrific plane accident, what would be an appropriate amount of days to wait to ask the new widow out?