I'd guess the issue here may be that your dog actually needs more exercise. A 14 month old male will be absolutely full of energy.
Healthy dogs need about an hour of active exercise -- and active generally means more than a leisurely ramble and definitely more than a 20-minute walk. EG alongside a vigorous walk, the chance to play fetch, really run and so on. I'd agree with above suggestion that fencing a portion of your property would be a lot nicer for a dog -- and make life considerably easier. Please do not consider those horrible elctric neck collars ("electric fence") -- these are well-linked to serious behaviour and fear aggression issues in some dogs but are useless -- if a dog goes through it the likelihood is it will run and run and not risk going back to the house side of the 'fence'. Also anyone or thing can come take a dog left outside with one of these fences. And they shock dogs on the neck -- in this breed, definitely something to avoid with the risk of syringomyelia already significant in any cavalier.
A fenced area would allow for safe dog games and a lot more active fun.
If this is impossible for you, then the issue is probably alternatively, getting your dog out every day for vigorous exercise early or mid-day, so that he is happy and tired and asks to go out the rest of the day, primarily to relieve himself. If you cannot give him this kind of exercise and have the opportunity of sending him to a dog daycare facility where he will get lots of exercise and play, that's also an alternative.
I have a 10 year old dog that remains extremely active and needs significant exercise, so this is likely to be a longer-term issue that comes hand in hand with dog ownership and is of course, a great part of the fun of having a dog!
I'd just add that trainers would generally view tie outs as very dangerous precisely because (as correctly noted above) they can wind around legs or neck or body and constrict/choke, and also can be very much contributory to serious behaviour issues (chains, ropes or retractable are all problem solutions unless the person is right there with the dog, which tends not to be what people get them for. As a rule I'd never use a chain for anything). The only ones considered OK for SHORT periods outside are overhead lines where the dog can range back and forth.