Why is my wife so frigid and inattentive?

The best I get from my wife is a peck on the lips and a lot of empty promises regarding adult activities. I am so frustrated. I have run the gamete of showering with gifts, complements, weekends away, love notes, texts, and praise in front of others to totally ignoring her and sleeping other places in the house. No Change, no reaction, nothing!! She is a zombie and more of a roommate than a wife or lover? She is 48 I am 46 and we have one child, age 7. She and I both work full time. She is very pragmatic about chores, daily tasks, our son and her job. She is very attentive to her old college friends, both male and female, and seems excited when they are around. She insists on splitting every bill regardless of how big or insignificant. She also insists on equal time for everything such kid after school activities, mowing the lawn, groceries, etc. She will not initiate anything like vacations or other activities other than for or with her friends. Its sad and I have no answers. I feel very very trapped. I would leave if not for our son.