Well, Aya, let me explain...
I don't think anyone was trying to be down on you or anything, so please don't take offense. The reasons why this is a bad idea, possibly, are that bringing up and expressing the memories of an ex tends to either:
a) Depress the person if they miss the relationship
b) Bring out the ugly side of a person if they're hurt and lashing out about the relationship
c) turn off others that might be interested (learned this the hard way... most people don't actually want to hear about your past relationships, either because, like a, they think you're not over them, or like b, they don't want to hear all the bitterness, anger, etc...)
So, I think that's where that was coming from, but call me a fool... I certainly don't mind speaking about my past relationships, and bear no ill will toward any of them. I'm kind of a different duck in many ways, and I believe that if you really loved someone...regardless of how hurt you are by them or the loss of that relationship, you wouldn't be hateful or bitter or anything...
Usually acting or feeling like that is just our own selfishness when you really boil it down.
(Also, as Christians, we should be pretty big on love, forgiveness, etc... *see Matthew 6:14-15* )