Not feeling the need to get married is one of the massive benefits of dating and interacting with people at a later life stage.
For people in their 30s or 40s and maybe even their 20s what they're often really focused on is finding a partner, getting married and having kids.
Not having anything to prove and not needing to go through with the wedding demonstrates a lot of security in the relationship. You already know how much you mean to each other and you can enjoy it all and have fun.
If you start to feel like you should get married because of what other people are thinking, this can actually speak to more insecurity within the relationship or cracks developing.