If both of them work hard constantly to keep that love on fire
no it does not....it changes in to different things and sometimes you stop all together. the difference is if you stay together and fall back in love. That is what makes a relationship last. i fell in and out of love with my husband. I still remember when i fell back in love with him the 2nd time. You do have to work at it though you can't just let it slip away. But in the same respect it takes 2 to tango and if one isn't working on it eventually it will fall apart.
.. Nice idea but you need more than love to make a forever ..