i know how you are feeling now even though i'm only 19.
i might not face the same situation as you, but i can say that i
once faced a similar situation.
just listening to advices alone would not help much. advices would
only be a guideline as to what you can do to relieve your passion
towards your wife.
try looking at your wife in a new light (treat her like a new
date). buy her a new dress and take her out to dinner. shower her
with passion like you once did during your courtship days. plan a
little something special for her that night. try incorporating
toys/role-play into your life. make that night an unforgettable one
and soon you'll have a changed attitude towards her in and out of
bed.