Still carrying the torch (1920s) for an old flame? You actions are skewed — in more ways than one. It begins with the Latin torquere, "to twist," given how the earliest torches were constructed of frayed rope, oiled or tarred and twisted at the end of a stick.
The torch you carry has a long tradition behind it. In Ancient Rome, funerals were held at night lit by torches carried in the procession. The larger the number of torches, the greater the respect accorded the deceased.
This tradition was mimicked in late 19th century America with the torchlight parade — a major part of every political rally. The most enthusiastic supporters of the candidate carried the torches. If you were a torchbearer you lit the way for others, a phrase which today makes you "a crusader of sorts."
The respect and dedication afforded the deceased during the Roman funeral and the enthusiasm and pomp of the torchlight parades are similar to the feelings we carry about a love long past — memories we hold of old flames and the heat they generated.
Alas, love's flame may have long since burned out for them — but not for you. Your love burns as strongly as ever. You still feel the pain of that unrequited or non-reciprocal love and memorialize your sentiment for a relationship now deceased — carrying the torch for them — hoping against hope that somehow, in some way, that passion will rekindle.
Lost amidst the processions and parades is the Ancient Greek relay race in which a lit torch is handed from one runner to the next. Maybe it's time you also considered letting go and simply passing the torch (late 19thC.)