New here - and struggling

Hi everyone, I am new here and I hope I am posting in the right category. Feel free to scold me if I'm not! I am a 23 year old woman in a serious relationship with an adult adoptee. He went from a neglectful/abusive home with his biological mother to foster care, then was adopted at age 5. In addition to being adopted as an older child, there are a few other things I feel were complicating factors. He is Hispanic and was raised by a white family in a small, predominantly white town (this did not go unnoticed by the people around him). He has ADHD and was quite a handful as a child. He had a very contentious relationship with his adoptive mother (who still refers to her family as his adoptive family...) He later did some time in prison, and his family has since stopped communicating with him. I met him shortly after he got out of prison. He is a wonderful person with a huge heart and my family has welcomed him with open arms. However, we have had issues off and on with dishonesty, him having trouble opening up to me and me feeling rejected, etc. I am sorry this is so long but I believe he has some serious attachment issues and I want to understand him the best I can. I have no intention of walking away, though I know in some ways he wants me to just because it is what he knows. Any guidance on how I can best address issues I have with his behavior without making him feel like history is repeating itself?