Hi amie;
Welcome to PC. There are lots of people here that can offer good guidence. Do you have a specific problem in your marriage or is it just a feeling in general that things are changing? Relationships do change over time but, if there is genuine love it can last a lifetime. I have been married 35 years and I got married very young, in fact too young.
I've had many ups and downs but, overall the good outweights the bad.

Join in and get advice as well as give it.

Have a great evening,