It can and many times it does. For example if you are very close with your sibling and you share everything with them, there will likely be shift from them being your main confidant to your spouse being that person. It isn't something that you purposely do, but it is just something that happens over time. Likewise as they find someone that they want to spend the rest of their life with, that will shift as well.
You are still siblings and you still love each other, but that closeness that you once shared will probably be gone to a certain degree. It may make you sad, but you shouldn't necessarily see it as a bad thing. It is just the way things happen.
In the end it doesn't have to change it any more than you want it to. As I stated, there will be changes, but you can mitigate those changes by still reaching out to your sibling. Try to talk to them frequently. Continue to share with them the way you have in the past. You can both appreciate and respect each other by understanding and respecting the new relationship that they have started.