Update: I'm incorporating what was discussed in the comments (thanks fdb).
A literal translation could be:
A viro ad mulierem
Or the shorter:
Homo ad mulierem (Man to woman)
I prefer mulier over femina. Femina is, so to say, more biological, and also applies to female animals. Mulier, in turn, is more human-specific and arguably more fit for romanticism, since it's ambiguous and may also mean wife (if in context!... so don't worry).
Ad + accusative (ad feminam, ad mulierem) is the standard way to tell to whom a letter or a poem is addressed to.
Ab + dative (ab homine) is a way to tell who the agent is, but the nominative (homo) is also common (for example in letter openings).
I can think of three ways to say man: vir (male correlative to mulier), masculus (male correlative to femina) and homo. The latter means man in the sense of human being, but has also the secondary meaning of man as opposed to woman (e.g. by Plautus in Cist. 4.2.57).
You could even make a more compact version, where a verb and an object are implied:
Vir mulieri (a man [writes/reads this poem] to a woman)
Here, the dative (mulieri) makes the noun the indirect object (i.e. the recipient) of the (implied) action.
I like this one because of its compactness, ideal for a motto or for engraving. Its perfectly idiomatic in this context, although it could sound forced if spoken out of context.
Similar constructions using the same structure are:
Masculus feminae, homo mulieri, etc.
A problem (or a potential advantageous fact) is that feminae means both to [a|the] woman and [a|the] woman's, hence masculus feminae can be read as both man to woman and woman's man. The precise word choice is up to you, depending on the nuances you want to give. You can even mix them (masculus mulieri/vir|homo feminae) but:
- Make sure to keep the right word endings (or the actual meaning can change)
- Keep also in mind that the mix could sound more or less as good or bad as these sound in English: male to woman, man to female.