What I feel is that I have a really hard time imagining Jade and Kaldur ever getting along long enough to do more than share Roy between the two of them and try not to step on each other’s toes.
I can def. see Roy in a relationship with both of them at the same time (with everyone knowing and being happy with the arrangement, of course) but while I can see Jade being antagonistically sexual towards Kaldur (cough cough that scene where she poisoned him in Infiltrator cough cough), I can’t see them being romantic with one another. Kaldur’s just too straight-laced, and I honestly don’t think he’s ever had to wrestle with his own darkness the way Roy has. Jade and Roy work because Roy knows where she’s coming from on a personal level, not just a conceptual one. Kaldur could probably see why Jade is who she is, but I don’t think there would be enough fellow feeling there for them to really connect.
I can see all three of them raising Lian, and even cohabiting, but it’d be a strictly Kaldur/Roy + Roy/Jade arrangement.