Why do I miss him this much ??? what is wrong with me!?

I'm married,my husband is the only guy I've been with.we are a happy couple,honestly.and I am satisfied with my marriage.there is no betrayal or sth like this.I used to chat with one of my friends,we used to be in the same university.it has been 3 years the last time I met him.now he is in another country.we were just normal friends,just chatting u know !?but recently he told me that he fell in love with me,and *** up everything, I told him that he did the wrong thing by telling me that he is in love with me.I ignored him and never saw him again,it has been about a month , since the last time we chat.but i miss him sooooo much.I know I did the right thing .don know what to do,I hate myself to have such feeling about him.I told my husband about him , he hates this guy,he is right.he tells me that he is a jerk,and want to ruin our marriage.but why do i miss him anyway?I feel like ****..I wanna keep my marriage but during the day I think about him,at work,at night,in the morning...It's killing me,what should I do ?do u think just time can help me ?why is it like this , while I love my husband ???do u think it is a normal feeling? :(