The aim of stylistic analysis is ultimately to explain the choices that a person makes, in speaking or writing. If I want to express the thought that ‘I have two loves’, there are many ways in which I can do it in addition to that particular version. I can alter the sentence structure (It's two loves that I have), the word structure (I've two loves), the word-order (Two loves I have), or the vocabulary (I've got two loves, I love two people), or opt for a more radical rephrasing (There are two loves in my life). The choice will be motivated by my sense of the different nuances, emphases, rhythms, and sound patterns carried by the words. In casual usage, I will give little thought to the merits of the alternatives: conveying the ‘gist’ is enough. But in an artistic construct, each linguistic decision counts, for it affects the structure and interpretation of the whole.

It is rhythm and emphasis that govern the choice made for the opening line of Sonnet 144:

As the aim is to write a sonnet, it is critical that the choice satisfies the demands of the metre; but there is more to the choice than rhythm, for I have two loves would also work. The inverted word-order conveys two other effects: it places the theme of the poem in the forefront of our attention, and it gives the line a semantic balance, locating the specific words at the beginning and the end.