Nick Carraway in The Great GatsbyWatch
This article on Google Scholar goes into this and I think it's quite interesting. It really looks at the comparison between Tom and Gatsby, examining the strange way that Gatsby is exonerated whilst Tom is disapproved of by Nick. I'd recommend at least browsing it if this is an area you're interested in.
My own opinion is that Nick, whilst maybe he doesn't conventionally love Gatsby, does at least have more than platonic feelings for him. Though, perhaps the character has yet to realize this? It's mostly evident when Nick sees that Gatsby has "something gorgeous about him"...