Can my boyfriend claim my 2 kids if i made over 4,050? He paid over half of their income last year also.

My boyfriend and i lived together all year in 2017 suppirting my 2 children together. We can not file together as I am still legally married. My ex husband can not claim them as I have a court order stating I am the one That gets to claim them. My boyfriend made a lot more money than i did last year and he helped pay for my children. I made around 6,000 last year he made a little under 20,000.