you won't die if a love spell backfires. if a love spell backfires, you might fail a test, or trip, but most likely the person you cast over will hate you instead of love you. if you want to take it off, theres a couple spells and cleansings you can do to undo the spell. here's some easy ones from the site:
To Undo a Spell: http://www.spellsofmagic.com/spells/spiritual_spells/banishing_spells/6165/page.html
Undo Spell: http://www.spellsofmagic.com/spells/spiritual_spells/binding_spells/1218/page.html
if the links don't work, go to the spells section and type in 'undo a spell' into the search engine. the first and the third one are the ones i linked you.