Dale is wise to her ways
Well he is her boyfriend and has lived with her for a while. I imagine that he's got to know, understand and to a certain degree, learned how to live with Marigold's most obvious quirks.
Actually, was it ever established that they moved in together?
I'm fairly sure that Dale & Marigold haven't officially moved in together yet. I looked into the question earlier this year and shared details of what I found in this WCDT:
https://forums.questionablecontent.net/index.php/topic,34884.msg1463085.html#msg1463085QC time usually moves very, very slowly (except when Jeph does a deliberate time skip). The argument I made back then - that it hasn't been more than a couple of months within the comic since we last saw Dale & Marigold at their separate apartments, based on the storyline about Claire's exams & job hunt - still holds up in my opinion.
I actually doubt its been more than a few weeks in QC since that post of mine from May. Edited to add:
I just had another quick flick through looking for time cues and it turns out that I'm no more immune than anyone else to thinking more time has passed than is actually the case. A more accurate estimate is that no more than a couple days have passed in QC since that post I wrote back in May (around comic 4526-4530). Careful reading reveals that comics 4531 right through to 4594 all take place within a single 24 hr period. 4595 is the morning after that according to the title. And this day we're on now (which started on 4597) is likely the same day as 4595 though it's possible it could be a new one.
Also, if they had moved in together - surely they wouldn't still be both trying to sleep in Marigold's single bed which was part of a joke in one of the comics at the start of this arc... Dale had a larger bed in his apartment. It doesn't make sense that they would move in together in Marigold's place and keep her single bed instead of his larger bed. In fact I wouldn't be surprised if we get an arc about them officially moving in together at some point(*) - I get the impression that they are in what might be best described as the "pretty much living together, much of your day-to-day stuff has migrated to their house, but it's not official and you still have your old place" stage that quite often happens in a relationship. Like Marten & Claire were before they talked about it and made it official.
*(I nearly said "soon" instead of at some point but "soon" in QC time - ie. a few months in universe - would probably be next year or the year after in our time)