No Man is an Island

So I had quite the unexpected conversation with a male friend yesterday, and it's made me consider whether people can fundamentally change over time.  "Bob" and I have been friends for several years but never particularly close...we mostly see each other within our circle of friends, occasionally do an outdoor activity together.  Bob is a nice guy, but in the past has often seemed excessively promiscuous, always leaving me with a feeling of defensiveness towards his frequent casual advances.  Nothing has ever really happened between us per se; he isn't my type, and the one time we tested the waters it wasn't for me, but we've done our share of platonic snuggling in front of the tv.  In addition to his loose ways with the ladies, Bob also tends to shy away from meaningful conversation, preferring rather to joke around and have a good time "in the moment."  So it came as a complete shock when we were hanging out following a group activity and he responded to a casual question about his childhood with real conversation!  Bob and I ended up talking late into the night trading life stories and discussing our respectively fucked up childhoods, then sitting in snuggled silence on the sofa for a while.  The whole experience was rather surreal...we really connected, and he openly acknowledged as much.  It was definitely the first ever interaction between us where I felt entirely comfortable and not objectified in any way, and definitely the most meaningful dialogue we've ever had.  It got me thinking about Bob's lifestyle and the subtle differences I see in him now compared with history...is it possible that Bob is evolving into a healthier more open person?  Did the conversation occur because I was more open to the experience?  Or has he simply changed tactics in his ever pressing to have sex with as many [attractive] women as will have him?  Or perhaps he subconsciously trusts me enough to open up following our recent [platonic] drunken skinny-dipping adventure? The whole thing blew my mind, and I'm hoping it hails future improvements and many more deep talks.