Boyfriend deploying for 9 months

Taylor
Hey guys!!! So me and my boyfriend have been together for two and a half years, he was my best friend all throughout high school and now through college. He is in the military and is getting deployed in March of next year... He's 100% faithful to me and I trust him completely... But is it normal to be worried about him having sex with another girl while he's deployed?! We are sexually active (obviously) it's not like sex everyday kind of ordeal, but it's frequent.. Ive talked to him about my concern and he told me there is nothing to worry about he would never do that (& I believe him, just need some reassurance) so any military wifeys out there? Or anyone that can relate to how I'm feeling?