In fact we will be celebrating our 20th wedding anniversary this summer, and in fact we are happier now than ever before. Only you can judge the best way to tell your wife you are bisexual. You may not need to drive her up a mountain, but I do suggest a quiet place where you can expect privacy for a few hours. Avoid public places like bars or restaurants. There is never a good time, but certainly avoid overly-stressed and tumultuous periods.