I have a buckle but no shoes. I wrap around and hug you from your middle Unlike you ex, I hold things tight and together

I come in many forms, though my purpose is the same. Some let you escape, some will end the game. Live ones grant mercy, another day spared. Quick-kill ones are kinder, when death is declared. Glue should be avoided, a measure of last resort, and a prowling house cat is nature’s own sort.

Only the winner may take me home, the loser might say I'm half empty. What am I?

You may draw me, open me, hide in my folds. I am who you think to call at the end of a show. I offer you darkness, I shield you from prying eyes, I move aside for the sun to glow.

The ancients used it to battle at a distance. It is how the sophisticated catch the olive in their martini. Append mint, and you may taste it first thing in the morning and last thing at night.