I'm sure a lot of you guys have dealt with this before - how do you help a young child cope and manage the feelings and thoughts that you've abandoned them?

I have a 3yo daughter with my ex, and the child told my ex several times in the last couple days that "daddy ran away and isn't coming back". This is something she has never said before and usually she just asks to video chat me. My ex challenged her but apparently she insisted that it was true and threw a semi-tantrum over it. I think this is a little more than "just being a toddler". When I video chatted her this evening I had asked her to help me understand why she felt that way when it clearly isn't true as I clearly love her and don't want her to feel like that - I also made it clear that I wasn't upset or hurt by what she said - but the child didn't want to talk about it and acted extremely withdrawn. I reassured her that in just a couple of weeks I will be fully "back" and living <1mi from her, potentially seeing her equally as much as her mother does (which we have agreed upon and settled out of court for)

Ultimately, I am saddened & disappointed because after a nearly 18mo long battle about whether I should have any custody at all (ex came to the table demanding unwarranted sole custody and maximum child support per my income). The whole time I had probably said to her dozens of times "you're hurting our child, equal custody is the only outcome that is fair and you're just delaying the inevitable (modus operandi for the state is 5050)." And to add insult to injury, just the other day I confirmed through a state's child developmental analysis report that my ex was leaving the child with a respite provider overnight several times per week and having her live-in boyfriend take her to daycare instead of even offering for me to take her, sigh.

Anyway, any insight into reassuring your children you haven't abandoned them? Did something specific work for you?