This is most definitely true. In my case I know I loved him way more than he loved me when I was really young, still in high school, and he was in college. He broke it off "for my own good" (his words at the time), and I spent two years heartbroken and always missing him and wanting him. I had other relationships during that time, but I always made it clear to them that the one I loved was this other guy (not very good for the relationships), plus various people I would talk to constantly about him. I was stalking him, trying to figure out the girls he was seeing, always trying to talk to him, but he never returned calls, e-mails or messages except a few times. It was a full on obsession, and not a too healthy one at that. It wasn't until -- and here's the ironic kicker part -- I started to get over him, that he started coming back to me.
I was pretty damned surprised, since I always figured that it was a lost case, that what we had was all an illusion, and that I should just move on. So right as I was moving on with a new guy, he started talking to me again, paying attention to me, going so far as to talk to me just about every night. I mean full on re-pursuit that caught me way off-guard. He told me all the stuff that sounded right, like how he missed me the entire time, too, but stayed away for my benefit (and maybe it was true, but we'll never know eh?). But I was still hurt, and so going back into the swing of things he had to do a lot more pampering, begging, listening to my complaints and trying to sooth the built-up pains from two years.
So shortly after that we got together officially, moved in together after about a year, in my freshman year in college. During the early course of our relationship I just wasn't all that into him. I felt like I always loved him way too much, and it wasn't good for me to keep loving him at that maximum level. At that point he was the one who wanted to marry me, but I was the one who wasn't ready, and wasn't even all that sure that he was the one. In fact at times I was looking for ways to get out of the relationship, so I'd say he loved me way more than I loved him during that time.
After knowing each other 8 years and living together for 5, things fell apart several times then got patched again. In this past year though, I came to several revelations, and so did he. We both wanted to be with each other for the rest of our lives. We both had to make certain sacrifices, but his were more difficult since his habits were rather damaging (alcohol particularly). Right now I think it is something like 40% on my part and 60% on his part. He tells me things like he doesn't feel like he's good enough for me (I used to feel that way when I was a schoolgirl!). But really I think he does make more of an effort than I do.
Thinking it over, I'm now scared that someday he'll love me less than I love him... maybe that's why every now and then I'll ask him if he still loves me, and accuse him of not loving me anymore, to which he always replies with "I love you more than anything in the world!" Yipes, don't let me become cynical about love again! ^^;;