Just need to vent & need support

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So I've been talking to this guy for almost a year now.. I'm a single mom. My son was already 8 months old when we met.. and I fell in love with him. But he doesn't want to commit to me, even tho I've done everything in my power to show him im worth it.. he makes me so happy but he said he just doesn't feel that type of love for me to make me his girlfriend.. and that the main reason is my son.. that he doesn't want to be a step dad... why is it that once us women have a child we are deemed unvaluable and unlovable by men.. I don't want to keep bringing different men around my son.. he is the only one I want but he's 19 im 21 he's just trying to live his life I get that.. but I literally don't even desire other men at all. When he was fucking another girl behind my back I felt it in my chest when he was around her. Like it would get harder for me to breathe. I just want to be enough for him. He says I am but if I was actually enough why won't he commit its been almost a year I've never been with a guy that long not even my bd. I guess my question is how do I get him to love me? How do I make myself worthy enough? He tells me I already do more than enough (I cook for him, buy him food or other small things he wants, have helped him get a job, smoke him out, always Give him sex... I am running out of ideas in order to prove myself.