How do I get closure?

I ask a question yesterday: http://www.fluther.com/120977/i-need-help-coming-up-with-something-to-say-to-my/

Anyway I got some really great answers (thank you!), and he’s texted me once today, to which I haven’t replied. I think I might just give him the silent treatment for a few days; give him a taste of his own medicine. Then depending on how he reacts maybe I’ll say something, but keep it short and sweet. I wanted to clear up the Twitter thing. I myself do not have Twitter, but he sent me a link to a ‘twitpic’ he had uploaded weeks ago, that’s how I came across it. I then decided to look at his profile for an answer to why he has pretty much stopped texting me. I know it was kind of an immature thing to do, but hey, his profile is completely public…
I discovered that the girl he is going after is his ex (Which is totally gross in my opinion considering he’s 20 and she’s like 15 or 16..)

Anyway.. I don’t know how I feel about completely cutting contact with him without any kind of closure. Any advice on what to say/do?