I am engaged to a lovely guy, and plan to get married in June. However, last night he admitted to me that he is bisexual. Could he be cured? And if so, should I go ahead with the wedding?

Huge numbers of men are bi-sexual. And some of them do manage to make reasonably successful marriages. But very often, they continue to "play away" after they get wed. That might not be very easy for you to cope with. There is no way you could get your man "cured" of being AC/DC. So think very carefully before you agree to marry him.