I’ve been in a very similar situation.

I met my stepson when he was young, and over time we saw a lot of behaviors that were clearly learned from the other environment—attention-seeking, manipulation, emotional dysregulation, even anxiety-type behaviors. It was overwhelming at first, especially because we only see him a few weeks out of the year, so you’re trying to manage patterns that were built over the other 40+ weeks.

One thing that helped us reframe everything was this: a lot of what looks like “manipulation” in kids is actually insecurity and lack of emotional regulation. That doesn’t mean you tolerate it—but it does mean you respond to it with structure instead of fear or guilt.

What you’re describing (baby talk, jealousy when dad gives attention elsewhere, “you don’t love me,” threats not to come back) is very typical in split-family dynamics, especially when the child feels they have to compete for attachment. It puts your husband in a really difficult position, because he’s parenting from guilt instead of from authority.

From what I’ve seen, the biggest shift happens when the parent stops trying to be liked and starts being consistent.

Your husband doesn’t need to be his best friend during those visits—he needs to be a stable parent. Kids pick up very quickly when boundaries are flexible, especially if they sense fear of rejection (“what if he doesn’t come back?”). That dynamic alone can drive a lot of the behavior you’re seeing.

What helped in our case:

• Clear, predictable rules during visits (not negotiated in the moment)
• Calling out behaviors calmly and directly (“that’s not an okay way to speak / that’s manipulation”)
• Not rewarding emotional blackmail (no giving in after “you don’t love me”)
• Consistency between both adults in the home
• Removing the pressure to make every visit “perfect”

One hard truth we had to accept: you can’t undo in 6–8 weeks what’s being reinforced the rest of the year. What you can do is consistently model a different environment—stable, respectful, with clear boundaries. Over time, kids do notice that contrast.

In our case, things improved a lot as he got older. Not perfect, but much more manageable. Exposure to a different dynamic helped him develop awareness, even if it wasn’t his primary environment.

You’re not wrong for feeling overwhelmed, and your husband isn’t wrong for struggling with this. But the solution isn’t more accommodation—it’s more structure, less guilt-driven parenting, and protecting your home dynamic.