Yea I did just that and you were right, the marriage starts on the next sunday. But why the hell does the game just stop after the ceremony and you get a generic "they lived happily ever after" cutscene? I thought you could actually have a wife in-game and you'd get new dialogue options and maybe you could even move together. That's honestly so disappointing...
Well, the game needs to stop and end at some point. Having all kinds of "after" stories, especially with the amount of possible combos in the game, would be a really huge endeavour. Moving "together" with any people not from the home harem - so how would they react? It would be a different story. I get that it may be anticlimactic to suddenly have the game end, but yeah, basically everything you can do is before the marriage. You can go on indefinitely without any and enjoy. In the end however this game will always have a limited amount of content, and will need some point to wrap it up. Well, for some it may not even need that, but for others it might.
Also, you possibly just unlocked NG+, so congratulations on that. Should ease any replay.