My husband just got promoted and he is gonna be travelling frequently, short trips though. I should be supportive but I'm getting freaked out on what may possibly happen on business trips. Am I being overly paranoid?

Shouldn't you be celebrating the fact that your husband just got promoted? Sorry to be blunt but yes, you are being paranoid. Traveling for work is very common these days and if your husband wishes to cheat, he can do that without going on a business trip. Also, you will have some alone time that you can put to good use. Pamper yourself to a good spa, chill out with friends :)