I mean, it’s all about setting good boundaries clearly.
That goes for partner, parents, and you. Each of you (and your parents separately for that matter) can freely place limits on how often visitors are welcome.
And, as long as it isn’t done in the wrong way, a couple can freely negotiate how often and how long the partnership can handle one partner visiting other family. Kinda weird for it to be an issue out of the blue like this post makes it seem, but that’s only partially relevant.
By wrong way, I mean ultimatums and heavy handed coercion.
But, and this is where that partially relevant comes in, why is it such a significant concern that you’ll go to their house too often/too long? That’s a pretty dang specific worry, and I suspect that the answer to that question would lead to better suggestions on how to handle the boundaries involved. It really seems like that’s a concern based in something important, whether or not it’s realistic. Addressing that concern would likely be as or more important than any actual decision regarding visit boundaries.
But that’s whatever, the goal as it stands is to work out what your partner and you each see as reasonable visitation boundaries, then (if they don’t match) negotiating those boundaries until they’re mutually acceptable.