It depends on a persons defination of love. Love can be for family friens and more. Honestly in love ppl say i cud die for her/him. But in my opinion i wud live for the person coz the person who is no more wud nvr wish for u to die.
And evn if ppl say if she/he is no more i wud die, i wud think the person is crazy, honestly very crazy. NO ONE, honestly NO ONE can love someone as a mother can, whether her child is ugly etc. But have u guys evr seen a mother say if he/she is no more I WUD DIE.
From my pov. i wud say ur teacher has either been unlucky or she herself don't wanna be in a real relationship.
The problem today is tht couples have divorce or break up for no reason. The don't try to understand each other they give up on each other. In my opnion yes love is unconditional, unless ur partner nvr understood u or u nvr understood him (also i believe trust is imp)