Two straight guys were my heart's desire, one in my late teens and one in my mid-twenties into my thirties. Obviously, there were the high school boys. Raised in the wilds of Lancaster County, we grew a fine crop of farm boys and small town guys who made my loins twitch. Two were friends-I-have-sex-with, one rather frequently in the rarely-locked church.
The first real ass-over-tea-cups crush-on-a-straight-guy (I don't know where these expressions-with-hyphens are coming from) was Jim. We met at a summer camp...both of us were counselors. He, a year younger than I, had family in Pennsylvania but lived in Florida. He was something of an outsider, not unlike yours truly, and I decided to get to know him at first glance. A bar not far from camp understood that underage counselors needed beer in great quantities to cope with the urchins in our charge, so we got drunk together a lot. (Of course, I also got drunk with other actual, real straight guys who loved show tunes. No...honestly. They sang the Buffalo Bills "Lida Rose" to my Barbara Cook "Dream of now, dream of then" counter-melody from The Music Man. We did that practically every night we were there.)
Jim was enrolled in Davidson College and couldn't stand it. We wrote lots of letters and he frequently took a bus north to spend the weekend with me -- I was never invited to Davidson. Our weekends together were usually spent drunk, with him trying to escape being a non-Davidson guy and me being gay in a small-christian-college-for-small-christians. He decided to transfer to my college in my senior year. We roomed together, much to my delight. But he'd rarely let me touch him and always told me that he just could never see himself having sex with a guy; he loved women. He married before the year was over, divorced her and re-married before he graduated. He knocked up the daughter of the headmaster at the school where he taught, which cost him his job and his second marriage. By that point, we'd kept in touch only by rumor and I haven't heard from him or his then-wife since.
Early in my time on the crew at the public broadcasting station where I spent too much of my life, my crew chief introduced me to Jeff. Jeff was freshly out of high school. Actually, he was freshly kicked out of high school because of his long, red hair which hung way the hell down his back. (Yes, there was such a time.) He got his GED shortly after he was expelled. I did not get a gay vibe from him, but he was friends with my crew chief, who was openly gay (not common at that time), so I figured he'd be cool. The two of them met at the community theater...my boss designed lights and Jeff helped him hang units and run the board. We were instant friends. In fact, we were inseparable for about a decade.
I'd never known anyone like Jeff. He was straight, about which there was no question, but he didn't make a big deal out of it as Jim did. He had no problem with gay men and admitted he was flattered by the attention. My boss and I shared an apartment (just friends); Jeff and another guy about Jeff's age (who became my boss/roomy's lover) spent much of their time there. Jeff and I got high together. He loved to listen to show music and rock and jazz. We frequently went to movies together. We nearly always watched The Mary Tyler Moore Show, The Bob Newhart Show, and The Carol Burnett Show on Saturday nights and then go out. Many people considered us an item. A co-worker thought it was neat that Jeff and I shared the same first letter in our last names so we wouldn't have to change our monograms.
Jeff and I were a couple without the sex. We started saying goodbye at the end of the evening with a handshake. One night we kissed and, honestly, I don't know who started it but that's how we parted every time thereafter. His mom, first very protective of him and apprehensive of me, grew to make me part of the family. For Jeff, I was ass-over-tea-cups and then some. And, I suspect, it was so intense for so long that it just sort of ended.
As long as care is exercised, I think I'd recommend a crush on a straight guy or two. It's probably unavoidable at first, especially if one is raised in the country or in a small town. The rejection is hard to take. Still, it's reasonable to assume an intense crush (and a stupid rejection) will happen. Just be ready for it, understand why he can't return your favors, and enjoy the friendship, frustrating though it may be.