For example, let’s look at this scenario : Bob and Sue are married, and Joe is Sue’s ex bf, with whom she has no intentions with. In the better world, this is how the conversation would go when Sue tells Bob she had lunch with Joe for old time’s sake after running into him in teh city.

Sue : I had a quick lunch with Joe today. He was walking by when I was heading to the sushi place I go to, so we caught up.
Bob : You did? I’m not sure if I’m exactly comfortable with that. You did date him for a while and you had a hard time letting him go for me.
Sue : I’m sorry Bob, didn’t mean to make it feel that way for you – I won’t do it again, it’s not like i’m in touch with him anyhow.
Bob : Thanks honey. I try not to be jealous but some things still bother me a bit, especially when it’s your ex. I love you.

Now, if they were insecure, as well as NOT very good at communicating, this is what would happen :

Sue : I had a quick lunch with Joe today. He was walking by when I was heading to the sushi place I go to, so we caught up. He’s a lawyer now and he’s very successful!!!
Bob : Oh great, Maybe I should call up Sarah this weekend too. I hear she just got a divorce.
Sue : What the hell is that supposed to mean?
Bob : What do you mean what the hell is that supposed to mean? I want to catch up with her for old time’s sake. She’s still kept a great body over the last 7 years. I want to know her secret.
Sue : So what, you’re saying I’m fat now???
Bob : I don’t know about fat but you certainly don’t seem to be too happy with just an accountant anymore, you gold-digging whore.

And then the fight goes on. Bob sleeps on the couch. The weekend comes, Bob doesn’t actually have the balls to call up his ex (obviously) so he hits the pub with his work buddies on a friday night, and ends up in a strip joint. They fight even more that evening and Bob gets the couch again.

Take a look at how your arguments are. Is it the first one, or the second one.