What i say on the internet seems to get back to my boyfriend

My boyfriend hasn't used his myspace in at least a year. He mainly used it when he was single and wanting to meet women, but hasn't checked it after we got together. I still use myspace because my intentions with myspace are not for dating or perversions - I genuinely use it to keep in contact with my party crew that live 1 1/2 hours away from me. I now have facebook so that the "older crew" i.e. my brother and some aunts and uncles can keep in contact with me. I said something the other day on my facebook status that had to do with a conversation I had with my cousin. But, my boyfriend's co-worker really read into it and asked him what I was talking about. Then, I get a phonecall asking me about my status - I was taken back because he shouldn't care that I have a facebook account and preceded to tell me that "social networking" is immature and that these "people" don't need to know what goes on in my (our) personal lives. My question is - do I delete the accounts? Do I tell him he's trippin'? Do I delete the friend that told him about my status? Is it normal for someone to dictate someone elses "social networking" if it's completely innocent?