Valtrex is not as effective on hsv1 as it is on hsv2. Does your boyfriend know whether or not he is positive for hsv1? There is a good chance he is already infected and doesn't know it If he is not infected, does he know that he can get an hsv1 infection by receiving oral sex from you? If so, he is an adult and making that decision with complete knowledge.
If you avoid oral sex when symptoms are present, the risk of transmitting your infection to your boyfriend is probably low, but there is no way to know without knowing how much asymptomatic shedding you have going on - it varies widely from person to person.