How can I find out the first time I made any contact with someone on Facebook?

[Endless13]

Ok so me and my boyfriend want to find out when we first crossed each other online..we know the date but not when it happened..Here's the situation, we both commented on his friend's picture/post (I wasn't friends with him or his friend yet) and well his friend deactivated that account so we don't know at what exact time we first met or what happened to that post/picture..it sounds stupid but we really wanna know..I remember I told him to friend request me and so I know that it was September 28th, 2012. I just wanna know if theres any way I can find out were the comments from diactivated friend's picture went..and if there's anyway to look at them and see the time? Thanks I appreciate it!