I feel quite sad for her that there's seemingly a gun to her head on owning up to the fact that Ned has zero romantic interest in her. She was made up when he knocked her up out of the blue, she so clearly believed that was her ready-made family despite her having no track record of a long-term romantic relationship and no practical security to suddenly bring a child into the world.
I think deep down, all she wants is a loving family structure behind it all, but it alludes her and has always alluded her because she's completely toxic and self absorbed and caught up in her own instagram smokes and mirrors.
Now she has to come clean that Ned probably never considered her a romantic prospect and that she's totally grand with co-parenting but Jesus like, who would be grand about that. It's so far from ideal, no-one would aspire to it. But instead of being honest about life just not working out sometimes, she has to play this "we're a great team" bs. They'll be a "great team" until Ned gets a girlfriend that's a lot more conventionally attractive than Shiv, or Ned wants to keep the baby in Ireland while Shiv wants to fcuk off again, or when life gets a bit too real in this new setup she has.