In this day and age, it's never too soon to invite a friend to a wedding. There is no implied symbolism or significance to such an invitation. All it means is that you like him and that you are inviting him as a friend. Nothing more. It most certainly does not suggest to anyone that you are ready to take the budding relationship to the next level, or that you now want exclusivity.
No "normal" male would freak out. He is likely to be more worried at having to mingle with a whole lot of strangers. You'll be there by his side!