I'll say what I've told most people looking for collaborations:
If you want to split it up 50/50, and you can't pay or can't offer any trade of skills, you have to be willing to take on more roles. Which means, you can't split up the comic as "writing" and "art". Comics have several layers that go into them, and as someone who does several on her own and have been part of other collaborations, I split them up as following:
Script
Storyboard/Sketches
Lineart
Flats
Rendering
Lettering
If you want something that's close to being 50/50 for a partnership, one person shouldn't be doing only the script while another is doing the rest. That's not 50/50.
Instead, I find it better if it's, for example, script/flats/lettering and lineart/rendering/sketches. This is just an example, and you can mix them up.
But if someone is proposing a 50/50 split, they need to do more than writing. Lettering and flatting are skills a writer can learn to do. It doesn't take much artistic skills to do these things. Just good direction and knowing how to pair the art with the writing. Even doing the sketches can help out. They don't need to look nice. They just need to look presentable so the artist can do the lineart.
I've done this with my collabs, and that's how they've worked. We split up the workload and got those comics done faster.
If you can't pay someone to do a comic for you, I highly suggest learning how to do some of the workload.
