I second what Meera and Arrowbound said. MC and I have two kids. TGIB has 3 kids with his ex. The kids come first unless ALL the adults involved are ok with whatever alternate arrangements have been made. Yes, it may suck sometimes and plans have had to change at the last minute, but that's why we're the grown-ups. We can have patience and wait if we need to.
Pan Female, Hinge in a V between my mono (straight) husband, Monochrome and my poly (pan) partner, ThatGuyInBlack