I understand that this might be difficult to understand or explain but, there is just one thing involved: being vulnerable.
For men like this, that have father issues, most times they don’t really know how to love or be loved by a woman, because they didn’t experience such from their parents, i.e they didn’t experience their father’s love for their mom, or their father’s love at all. So they learn to live without it and shield their hearts with all the shields they can find, taking on different hobbies and incredible dreams to keep active.
You must understand that without a father figure he has been forced to be a man for himself, to not be dependent on anyone, kind of a loner who has found comfort in being alone.
Experiencing your love becomes a vulnerability for them, a vulnerability that they have known to shield themselves from, so they eventually run and hide without a reason. for someone who has embraced being alone, being with you becomes uncomfortable, he starts to experience things he doesn’t understand because he is not used to these new feeling, or know how to deal with them. He then chooses the comfort he has known for a long time **Go back to being alone**
There is truly just one solution, you have to teach him to love you, without falling deep for him.