Getting unsolicited advice is sort of a rite of passage for those marrying (or going through every rite of passage - having kids is worse). But this might just save your marriage in the long term and will make your wedding planning a little easier in the short term.
Say Thank You.
Throughout your lives together, you will ask your spouse to do many things that are onerous and burdensome. You and they will do whatever it is because that is what one does - we sign up for it, we do it with joy, with compassion, with enthusiasm, or depending on how bad it is, civility struggling to be graciousness.
But to do something that we wouldn’t do on our own behest for someone else is difficult. It requires effort. When someone does something for you that requires effort, we say thank you. This is an obvious thing, but so often it doesn’t extend to the people nearest us. We feel they just ought to do it, "because."
But the truth is, that no one likes being taken for granted. And having people do things for you without saying thank you is taken them for granted.
When your fiance shows you all the wedding stuff that they have put together say, “Thanks so much for doing this.” If you are the person who has put it all together, say, “Thanks so much for looking at all this. Your participation means a lot to me.” Both of you are making an effort to do something that is out of the ordinary.
Get into the habit of just thanking each other and acknowledging effort. Just noticing and saying that you noticed really goes a long way.
Right now, send them a text and say, “Thanks so much for ...” It will bring a smile to their face and make their day just a little easier. It doesn't have to be a big thing - thank them for making coffee or for saying something that made you smile.