Who is Beyonce singing about? (4 Album)?

I get 1+1 and missing you etc because they're cleary about Jay Z but
when she sings Best thing I never had and I care I don't get who she
is singing about. They're all really personal songs and lyrics she has
written. I only know of one boyfriend before that... so all the love
songs are about Jay Z and the rest about the first boyfriend?

Any ideas?