Step parenting

My son doesn't have his father, he passed away, however, my boyfriend of 1 year still hasn't taken in the "father" figure for my son, he's there and plays with him, but he doesn't consider him "his son" at all....he has actually told me a few times that he will never be my son's father, which hurts a lot for me. I honestly have gotten to a point of wanting to leave and be on my own, but this is the thing, another side of me doesn't want to leave him??? anyone else have this problem?

    He has his daughter, however, he doesn't want me to act upon as her "mother"figure in our home....basically, like i told him, i felt like just a babysitter to you, not someone your daughter can also look up to when in our home, and in her mother's home.....when it comes to my son however, he gives him attention, but it does break my heart him saying "i will never be his father" which is true, he wont, but if you're going to be with me, you have to be part of my son's life as much as i am for your daughter" but i guess since we've been together only a year, its a touchy subject???
    About Toni Story
    Current: Kingman, Arizona
    Birth: March 17
    On since: Aug 6, 2014