I get the impression Picard is a "former Kirk". The character backstory does say he had an affair with his best friend's wife, so it isn't like he's Mister Squeaky Clean. It's more that by the time we meet him he's something a dark horse. Outwardly enlightened about the mistakes of his youth, but still harboring some of those impulses somewhere deep inside him.
There was no affair. The last time I checked, Picard and Beverly were only friends.
Picard lost the "former Kirk" in him the moment he got stabbed in heart by a couple of Nausicaans.