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I don't know what abilities you have, but I'm confident you can do a great many things, including, but not limited to, unfriending and blocking him on FB, blocking his number on your phone, blocking his e-mail address, etc.
The point made in the first couple of responses is that, even if this is illegal (and it probably is), it isn't likely to interest any law enforcement officer because it was a one time incident involving adults. If it continues, then it will be more likely to grab someone's attention.
Be sure your privacy setting is set for Friends Only. That way he cannot see anything you post on your timeline. Hopefully he will go away.