Never going to happen I guess

So basically my fiancé and I have been engaged for 5 years. We’ve discussed dates and have set a date twice and he will back out. the most recently we set a date for March. He even suggested we do crawfish and do it our back yard and then he backed out again. We’ve been together for 10 years. He’s always said he can’t wait to marry me so what’s his deal? He just says it’ll happen and then it never does. I’ve tried talking to him about it numerous times over the years, he will agree and come up with ideas but then backs out every time..