Locks upon a fence

Lovers place their locks
Upon the fence to say
"I love you honey
Till my dying day"
I guess the premise must be
As long as this lock stays here
You'll remain my precious love
I'll hold you in my arms; year by year...
Found one with a combination
The mind boggles with glee
Does he come; retrieve the lock
Bring another lover; under cover
Making believe that it's forever
All good till he's discovered