Here's why - I wanted to write the books this way because I like to pick books at random and not have to worry about what number in a series I am reading.
I remember going to the library a few years ago and picking up Katie MacAlister's 'Zen and the Art of Vampires' - I just loved the title and had no idea at the time that it was part of a series. I read it, loved it, and then looked up the author online to see what else she had written - loving the fact that I had read the 6th book in the series but it was a wonderful story all of it's own. Not once did I stop confused and wonder what the heck was going on.
There are a few other on going series that I like that run along a similar vein - so that's my goal, to create a series of love stories where the characters are linked so you get to see the couples you loved in previous books but the story stands alone so anyone can read it.
My 'A Beautiful' series currently had two titles - A Beautiful Struggle
and A Beautiful Forever, you can read them in order or pick the one that sounds the best to you! :)