Setting a rule or making anything taboo is asking another person to lie to you. Do you value knowing or not knowing? If you value knowing, then don't make knowing impossible by setting limits on truth.
In all areas of life, it is the lack of both honesty and unconditional acceptance that causes suffering. You cannot claim to want the truth and not choose unconditional acceptance--which is simply a decision for truth everywhere.
Lies will suffocate any relationship; causing mistrust, resentment, distance and loneliness. Being limited by someone else's demands—because you are afraid of what might happen, or because you want to protect someone else's feelings—also feels lousy and is completely unnecessary.
There is nothing wrong with you and, therefore, there is nothing wrong with telling your truth and living it. Same goes for your loved ones. If you love them, let them be who they are.
When there is perfect honesty combined with love, all issues can be dealt with and worked through. As you truly communicate, that blissful, energetic feeling of love will be kept alive. You will be blessed with an open heart and mind. Youthful energy will flow through you at any age. If this is what you want, unconditional love is the only way.