There's no "on the fence" with this one darlin'. Stay the heck out of it. What he said to you today proves he's still a douche. You got away, and its not your job, even though you have the biggest heart around, to try to warn, or "be there" for the fiancee'. If you want an emotional wife, and if you want to deal with that asshole more that you already have to, then dive right in. You have enough on your soul and spirit, though, so I would let the adults be adults, and take care of their own mess. Sometimes it takes us 2 weeks, sometimes 10 years to realize the good guys from the fuckers. How long it takes her is her bag, not yours.
Focus on yourself! Be there for YOU!! Don't let the vampires suck everything out of you. Fuck everyone else right now.
And you are the complete opposite of a loser, sweetie. When your down, thats when people want to come up and kick ya. Grab their legs, and flip those fuckers good!!