“He’s Jamaican, I’m French and we’ve been dating for 3 years. We are both internati asdfadsf ”

He's Jamaican, I'm French and we've been dating for 3 years. We are both international students and we might have to go back to our respective countries because we can't legally stay here. We want to be together and the only way would be to get married so he can come to Europe with me. We are both serious about being together but I'm afraid I'll always wonder if he really wants to be with me. We don't wanna loose each other. Plus I pictured any wedding day to be a big event, not to sign papers but if it's the only way to be together? Should I do it?