I would say that it's not something to end a relationship over, no. It sounds like he over-reacted to the use of the word love, and you should perhaps clarify to him that this is not passionate, but more platonic, and you should possibly inform him that ex's are ex's for a reason. If he can't understand that then perhaps it might well be something to end the relationship over, purely as he cannot understand your feelings on the matter.

I myself keep in contact with my ex's on a purely platonic manner - even went out for a drink with my two ex's and my fiancé. I'm still excellent friends with the one of them.

I can understand why he might have reacted that way, especially initially, but give him some time to let the true meaning of what you said sink in, and he'll have his foot in his mouth. I know I don't want to hear my boyfriend tell me that he loves any of his ex-girlfriends, but I know that I still love my ex-boyfriend, even though we were not right for each other. I mean, there is such a thing as a break-up that doesn't make everyone hate each other.

But really, just explain things to him. He's being irrational.

you shouldn't have said that out loud. no shit.

In order to even propose to you, he would have it set in his heart that through all circumstances...he should always love you and try to work through any problem...no matter how much it takes.
You made a mistake...and blabbed something that was taken the wrong way...and now everything seems to be the end?
If he cant forgive you, and work through this maturely...then darling he won't be a good husband. As husband and wife you must work together as a team...there will be by far HUGE struggles that lie ahead of both of you...it wont be easy.
You really need to be open with him, and talk about this. And as for your ex boyfriends...they do make us the woman we are today because we learn through heartbreaks...but they are yesterday and he is your today AND tomorrow. You need to focuz on him and let the other strings go.
Communication is key. TALK TO HIM! and seek marriage counsling before the big day...it will definitily be worth it to understand eachother more and learn how to work as a team.

As much as I like to stay a feminist and not have "male" "female" things, I must say that no man wants to hear that. It's Just like saying, he is not your best sexual partner. Just explain to them that they all have special places in your heart because each of them have taught you something that helped you in relationship which made you know HE was the right one for YOU. If he is so silly that he will drop you and call off a wedding because of that, he s stupid, and does not deserve you, he needs to come to his senses and see you are the right one for him as well.

As an engaged woman, I have told my fiance many things. That is not one I would ever tell him because I feel that he is the only man that I have ever loved. Not because I hadn't been with other people before him, but because no other compares to him. he made me realise that I hadn't loved all of the others that i thought I had. He taught me what real love feels like and I would never want anyone but him by my side. Saying that you will always love your ex's means that there could be a chance that you still want them (that is probably how he took it). I would die if my fiance told me that he would always love his ex. I can understand learning things from your exs but there should never be a reason that you still love them; you are no longer with those exs because something they taught you wasn't what you really wanted. Your fiance doesnt want to feel like you would choose them over him. It takes out the fact that he is the only special one to you. Its hard to say, but it wasn't a very good thing to say. Sorry.