I don't see a wedding ring, but the Netherlands are sometimes referenced in works with gays/lesbians in them as the place that they want to take the one they love (requited or not) to get married, since they have gay marriages legalized there. (As opposed to our perception of it, where it has legal weed in "coffee shops" and free health care for everyone.)
Since this artist tends to draw a good deal of yuri, it might be worth keeping that in mind when you look at this picture.
Yeah, but the meme in Japan is that you go to the Netherlands to do it.
I guess it's just got an international reputation as "Left-wingtopia" or something.
Plus, there's also that whole thing about most people from certain parts of the world not being able to tell Finland, Norway, Sweden, or even the Netherlands location apart on a globe, so they may just be saying "All Scandinavian countries are The Netherlands".