- they had no contact with other races until Malomedies was captured by asura

- their first human contact was Waine, who by all accounts was still a teenager

- in Caithe's memories from S2 the sylvari are still really isolated and the Secondborn had been awakening for months at that point

It is not inconceivable - in fact it is highly likely - that the sylvari developed their own cultural flavor for things like falling in love and getting married before they really encountered the human way of doing it. I think Caithe and Faolain, being the oldest canonical sylvari couple we know of (until Wynnet died), would have set the tone of the cultural romance of the sylvari.

The tradition of marriage in real-life human culture has its roots in the Jewish/Christian practice of a lifelong pledge of oneness to each other. Sylvari have no tradition or precedent like that, and their love works differently to begin with.

Sylvari don't fall in love with a person so much as a concept or ideal that two sylvari fall in love with together; so they're kind of pursuing this concept or ideal together and bonding over it. This is why, for a sylvari player, Trammander is not just a fan-pairing, it's almost lore canon. But anyway - ideals and concepts change and you change and your partner changes, so a breakup for sylvari is less brokenhearted - like if your partner changes and you don't you're just kind of like - I thought I knew you? and you know them of course but they're just not your type anymore and you have to find someone else with your ideal or concept, or maybe you also change because of the breakup, or something.

But anyway; so I don't think sylvari 'get married' in any traditional human sense where you pledge faithfulness and the law recognizes you as one entity and divorce is long and painful and often traumatizing and interactions with that person later are just kinda awkward at best. I think when a sylvari says 'I love you' to another sylvari and they say 'I love you' back, that's the sylvari equivalent of marriage, and it can and does end peacefully at any time more often than someone gets angsty over it.

I'm not saying sylvari don't form interpersonal ties; I'm not saying if your partner leaves you just have to find another one to be happy, because it's clearly not. See Tiachren and Ysvelta, from sylvari level 10, and when Ysvelta changed, either Tiachren tries to bring her back from Nightmare because this isn't the person he knew (and Nightmare adds a whole other dimension of complexity) and eventually has to kill her because he still loves who she was and Nightmare kinda cheated and stole her mind, or else he joins her in Nightmare because - I think she still had whatever concept or ideal it was that they fell in love with together, and doing it in Nightmare is the negative side of it was better than abandoning that concept or ideal.

I also don't think sylvari use words like 'husband' or 'wife' - the sylvari term is the gender-neutral 'dearheart.' The words 'wife' and 'husband' just feel wrong when we're talking about sylvari because those are human terms.

Now, if there was a romance between a sylvari and a human and the sylvari was like 'sure we can get married your way' - then that would be cool and interesting.

But like - making sylvari just planty humans culturally is lazy when there's so much potential. And I'm aware I didn't do anything special in this post, I'm just being picky about words.

But hey, it's a concrete system for romance that doesn't feel like humans that happened to be born as plants!