Husbands cigarette smoking is now causing tension

Co
I have been with my husband for 6 years. He was a smoker when I met him. I fell in love with him, even though I hated his smoking. We had our first daughter in 2011. He has always smoked outside, but he was made to wash and change before he held her. Now we had our 2nd daughter and she was born a little early and spent 5 days in NICU. Same rules apply, but I am now tired of it. I care about our children's health and I am upset that he is not even making the initiative to quit. I love him, but hate his smoking. I know I can't make him quit, but is there anyway I can encourage it?