This is less about MX records than it is your mail server configuration.
Quite simply, your mail server doesn't know that it's supposed to accept mail for johnbutzek.com, so when it sees such a message it assumes it's supposed to relay it to another server, or bounce it if the sender isn't authenticated/trusted.
Changing the MX may be valid, but it's not going to fix the problem. If the MX record points to this server all you'll get are 'MX points back to me' errors in the postfix log.
Instead, you need to tell postfix what domain(s) it is supposed to accept mail for. RIght now it sounds like you have it set for 'server.johnbutzek.com' and that's your problem. Change it to 'johnbutzek.com' and your problem should go away.