Kiddo says they don't feel loved since I've been around. What?!

So, I (34F) have been in SK(5)'s life for about a year, dating their dad (40M) for 2 years. The schedule has recently changed to EOW, and I'm not gonna lie, it's been terrible for everyone. SK and their dad are clearly sick of each other by the end of their time with him, and we only get one date night a week during those weeks.

We have all gone in many camping trips together, and spend lots of kiddo time with them - this is to say that I've been in her life for a little while now (with no complaints). Recently, we had some experiences where I communicated that I need him to start actually enforcing consequences, because the Disney dad shit was hurting our relationship, and I need more adult time with him. We now have two date nights a week, where his folks babysit, and consequences for bad behavior are actually enforced.

The other day in the car, SK said that they don't feel like SO loves them as much as he loves me. We immediately jumped in to thank SK for sharing those feelings, reassure them that they are loved and important.

SO says that he thinks sk's just testing boundaries, trying to see what our reaction is. I'd like to believe him, but I really don't know what to think.

Has anyone else dealt with something something similar?

Thanks

Edit: he has 50/50 custody - I did not know EOW means every other weekend.

Edit #2: I don't live with them.