Reminds me of my Sims 2 game the other week. My sims were engaged, they seemed perfectly in love, no problems, no cheating then it was time for the exchange of vows at the wedding and the groom rejected my poor sim... lol. I wanted to drown him in the pool I was so mad.
Anyway, idk why that happened, perhaps the game just has the chance (well I guess obviously) to make them reject the engagement. Perhaps you can try again?
Edit: Just read that you wrote you're going for the third time... Idk what is going on there. Did either of them ever have the non-committal trait? Because (idk if it's been fixed) but before if you changed the traits sims would still get moodlets from old traits or even just act like they still had the deleted trait(s).
Edit 2: Okay apparently my post was way late, just read the one above mine. Glad to hear you got it working lol.
