Best friends

Why is it that I can’t seem to have guy friends that are just friends. I have known this guy for absolutely years and he’s always liked me, even has a gf yet he seems to want me. I think he thinks if we hang out enough that I will fall madly in love with him. He’s a great guy always respectful etc and I know he has issues with his gf so I remain impartial and try to help him through things. I feel sometimes though that he wants more from me but I can’t offer that especially when he’s with someone and I’m also not in that place right now. I feel Like my heart is closed off. I just want yo be able to be friends and not have anything awkward really lol nothing is ever simple.