no one to talk to

I have no one to talk to regarding how i feel with the future with my boyfriend. I cant tell him about it cause i feel i might scare him. His ex of 4 yrs broke up with him because she wants to get married and he doesnt yet. I feel confused right now that i might be in the wrong relationship. I feel happy when we are together, but when i think about the future, i get scared that I might end up like his ex that got tired of waiting. Will you know from the start that a guy is someone you'll be with forever? Am i just overthinking? We've been together for 2 yrs. I am 28 and he's 31.