Why are gay guys so affectionate? ?

Ok that's a bit of a generalization but I've seen the same situation as mine repeated over and over. My best friend is a gay guy and he is very affectionate. He kisses and cuddles me all the time. We snuggle up watching tv, sleepover sharing the bed. If he's ill he wants me looking after him (even over his bf if he's got one at the time) and he buys me more gifts than he does anyone else (Inc his bf's). He phones me every day even if we have spent the day together anyways. He phones at like 1am just to say he loves me and night. He goofs around play fighting or touching my or and says I got a nice rear. All of which has made some of his bf's (and mine) in the past jealous. I love love the affection and I guess maybe it's cos they think it's ok cos it's clear compared to a straight male friend? Like if a straight guy kissed and hugged a girl all the time then she and everyone would read more into it? Right? Only as a straight girl who knows he's gay it still flips my switches and confuses me makes me feel things I wish I didn't as we are so perfect together but he's unobtainable :(