While you're figuring out what you want, you're not obligated to put your cards down. First, found out what this new person is seeking and if it matches with what you want. Maybe he is not seeking a serious relationship but to fool around.
If you absolutely do not want to be in a long distance relationship, then end it. There is no point going around in circles because that would give mixed messages to the other party involved.
Flirting is not necessarily a sign of something big coming up. Familiarize yourself with this new person if you're interested in them before you make your decision. There is nothing wrong with being friendly with someone.
As you get to know him a bit more, ask him open ended questions ex: what are his goals for his work/life style, where does he see himself in 2 years, etc. The responses will give you an idea of what his priorities are at this time in his life. You can also set a time frame for yourself ex 3-4 months and see where things go.