Prices getting silly high (unlikely with EE girls), a change in law and heavy handed policing, pimps and thieves taking over to make it more trouble than it's worth, something happening to make it impossible to do without getting caught, getting a partner who also really really loves sex, or getting HIV.
The most likely scenario is just that I get it out of my system a bit and it becomes a lot more of on occasional treat than a habit as my sex drive decreases with age. Or it may not, either is good, my bucket list is still certainly growing.