I so appreciate it when people bow in my presence even when its completely undeserved. But thanks for the esteem boost anyway.
Simply, your ex is a douche. Though, is the reason that you're writing this because he's been hot and cold towards you since you deleted him on FB? If so, then I'm inclined to think that his feelings are hurt. Not that it's an excuse but hey, in today's social media days, get de-friended is a big damn deal.
The other piece is - and this assumes that this isn't all stemming from your FB de-friend standoff - maybe he still likes you and isn't sure how to handle it. He's flirty but catches himself and then goes cold because he's unsure of what to do and you're not giving him any cues that would suggest that you're still interested.
Look, when men start acting inconsistent usually there's a woman involved. Congrats, you're his weakness.