No idea how to approach my own father

I'm 18, have lived on my own with my girlfriend since 17 and my dad really wasn't there much ever. He wants to have a relationship with me now and I'm not totally against it I just have a really hard time with him advising me on decisions I make or trying to "guide" me when he never gave a shit when I needed him the most. Really just looking for insight on how I might go about talking to him about that so we aren't constantly going into a grey area of things I'm uncomfortable with that he feels the need to address.