Should I keep trying

Okay, so i have a stepchild and I’ve know him since he was 2 and have been trying to gain his affection for 9 years. We’ve never really developed a relationship. Every time I feel like we are getting somewhere he retreats again and starts acting distant.

He told me his mother would tell him ima bitch and that I’m terrible before every visit. But with time he was able to see that she was lying. But I feel like he will always trust his mom and no matter how hard I try we will never get to develop a good relationship. And it’s strange because he spends his whole visit with me and he likes me but he’s stopping himself from liking me to much.

Well now I have a daughter and I don’t want to take time away from her, to try and develop a relationship with someone I’ve been trying to for years and he’s not reciprocating.

It was my birthday and he knew and didn’t even wish me a happy birthday. It’s crazy I’ve been at this for years, I don’t know what to do.

My daughter is my number 1, I love my stepson but there’s only so much one can do. He’s 11.

Edit: thank you all for your responses, I will keep trying and loving him as usual. I agree with you ladies I shouldn’t be looking for anything in return.