Jealousy???:(

My husbands sexual past makes me extremely jealous! Just thinking of him with someone else hurts me so bad. And to top it off yesterday was our aniversary and we went out to a restaurant. The waitress suddenly asks him his name and sayd you dont remember me? its ******. Turns out it was a one night stand he had once. I felt devestated. Especially because the girl acted like i wasnt even there. I stormed off and till today ive been upset. That event totally killed any self confidence i had. And made me even more jealous and hurt by his past :( any advice as to how to overcome this???:(