It sounds like he barely has any idea what he's talking about...or you two are talking about totally different things. Has this happened before with him? Has he done this to anybody else?
I only know his history in broad strokes. He has a "reputation," I just don't know the specifics. He hated the guy that I replaced - 3 months later and he is still publicly bad mouthing the guy. Very unprofessional, makes for a hostile work environment.
Is taking him out for a beer an option? I'd recommend nipping this kind of thing in the bud as quickly as possible; or it'll just spiral out of control.
If you can: be diplomatic, take him out for drinks after work one day and have a heart-to-heart. He wields a significant amount of power, and it'd be in your best interest for him to like you alot.
"How he talks about his ex-girlfriend is how he will talk about you."
Word substitute accordingly. There's a reason it's a bad idea for candidates to bad-mouth their current employer, and it's the reverse of this situation.
A general policy of mine is to avoid people who are frequently bad-mouthing other people. I think this is your key indicator of his character, and yes it does make for a hostile, and corrosive, work environment.
i am quickly adopting it as my general policy, too. i'm tired of the insecurity, neediness, and negativity that accompanies that mentality (along with the things you mentioned).