I had a mmf that lasted for 6 years, but that is more likely for a man older than 40 than a young man. We lose our possessiveness with age, which is why they can work so well. And the woman loves the attention and sex....but for a man your age, an mmf is likely to founder on the competiveness of young guys. Tell me true, do you like the arrangement, or do you like having sex with HER. I don't give you much hope for this working.....but you could try CL and find an older couple looking for a younger man...
GF, Wife, you know they do make excellent company. I married my best friend and we are even better fiends now after over 20 years later. Or are you just looking for some convenient company--hookers will do that too, most say that is a lot of what they get called on to do.