The speaker never tells us his name, but he does make one thing clear: the dude is totally, completely, head-over-heels in love. How do we know? Because he talks about it in every line of the poem. (Yeah, we're perceptive like that.) We can tell that he's kind of a deep guy, though; he's not in love with this girl for any superficial reasons like mega-hot good looks. Instead, the speaker is entranced by the deep mysteriousness of her soul. He doesn't quite know who she is, and it's this mystery that keeps him hooked. (Is this a healthy relationship? We don't know. Go ask Dr. Phil.)
Another interesting thing to think about is the way the speaker constantly refers to his lover opening and closing him like a flower, as in the lines "you open always petal by petal myself as Spring opens/ (touching skilfully,mysteriously)her first rose" (7-8). Now, typically, this sort of image would be reserved to describe a female, because women are stereotypically associated with flowers. However, most critics of the poem always sort of assume that it's a male describing himself in typically feminine terms. Why would they assume that? It's probably because the poem was written by a dude. At the time Cummings wrote this—in the 1930s—society was still pretty male-dominated, so the speaker could be using this gender switch-a-roo to really emphasize the power his lover has over him. What makes this guy a bit different from the stereotypical dudes of his time is that the power she has over him only seems to make him love her more.