His and Her Health

i dont know if i'm posting in the right forum about this problem regarding my husband's arousal. I've been married for a couple of months now but have not had sex a single time. He has a proper arousal otherwise, but when we're trying for it he loses it all at once, just before entering. viagra has not helped much. says he gets nervous. I have tried everything. try to support him n all. but its not working. have tried to be very patient, but its getting frustrating. should we consult some doc or therapist, what should I do?
can anyone suggest anything ? :confused: