My mii won’t get married

Two of my miis have been sweethearts for 61 and have lived together longer than that and idk if they’re ever gonna get married. I play almost every day and they’ve been at wants to marry for most of those days. Every time i play i feed both of them and give them head pats and make sure they spend time together. Every few days i’ll send one or both of them on a vacation. i’ve never even gotten the pop up for one of them wanting to propose. is there anything else i can do to try to get them married?