Just got engaged and my kids are pissed

So I just got engaged a few days ago and I told my three daughters thinking they would be happy. They are less than thrilled! I've been divorced from their father for about 6 years. I've dated off and on. I made the decision early on I would not settle down with anyone less than perfect. Well I've found Mr. Perfect! We've been living together for 6 months. He's amazing with my 3 girls so I'm a little thrown back from their reaction. I understand they are kids and don't see the entire picture here. Anyone else have this issue?? How did you get your/ his kids on the same page?