What happens to the 2nd male lead?

I think it's left ambiguous on purpose but the author is biased towards Lucas more than Ijekal because Athy and Lucas kiss in 126 whereas the final scene with Ijekal simply says he'll wait for Athy.

It's probably meant to cater to everyone's preferences. And I'd personally also be down for a poly ship, but I don't think a genuine poly relationship can really work with tense jealousy in the mix and so far there has been a lot of jealousy driven animosity between them. So I can't really picture them living a healthy poly life in my head.