What kind of parental consent do I need to take my child out of Sweden?

I'm going from the US to Sweden with my child to visit her father/my partner.

After 3 months, I plan on coming back since we're still waiting on Migrationsverket for a decision on my residence permit.

Now, since my child was born in the US, I don't know what kind of traveling consent I need from my partner in order to bring her to Sweden and back to the US.

Him and I are on best terms right now but I also wonder, what can I do to prevent him from keeping my child in Sweden in case he tries to do something like that?

Maybe I'm paranoid but I heard horror stories of mothers who take their kids to Sweden and can't leave with them because the father is against it, and they want a divorce. The mother then faces the risk of breaking the law if they stay in Sweden without a residence permit.

This a worst case scenario and I don't think my partner would do that to me but I'm trying to prevent my child from going through any parent drama if it ever takes place.

Is there any sort of agreement we can sign together? And is an American legal document sufficient for Sweden?