I can thoroughly recommend a cuckold situation.
My wife is 60 and I am 67. We decided about 4 years ago to try something different as our sex life was non existent. My cock is very small, and she wanted more. We tried just swinging, but it didn't really do much for us, but I did decide that watching her being fucked was turning me on. She was also enjoying seeing me watching her. Gradually her needs have increased, and she loves big cocks, and will do almost anything. I am completely sub, and do all of the cuck duties. She is very sub to her bulls, but totally dom to me. It is a great lifestyle, and I love the humiliation.
Go for it, you won't regret it.