I understand that studies show that cohabiting before marriage does not actually lessen the likelihood of divorce. I think this could be because before formal vows/commitments are made, people tend to be on their best behaviour because they feel less secure in the union.
Once the union is formalised the mask/veil is dropped revealing the full personality or character of one or both partners. The interpersonal dynamics change after marriage whether or not there has been cohabitation beforehand.
DH and I cohabited for a year before our wedding date. Only a couple of months into cohabiting we decided to get married and started planning our wedding. From the moment we made that decision we were effectively married. Nothing changed afterwards. Whatever we were, the other knew.
It leads one to wonder if we are just blind to the things that were always there, or if people change into something that they were not beforehand. I dunno, maybe both.
Sometimes people grow apart, but what I've mostly observed is that people ignore warning signs before they get married, then find the behaviors intolerable afterwards.
Perfect example: A close relative had an early marriage and divorce, no children. About six years later she met a man, fell in love and they decided to get married. Fly in the ointment? His family was Roman Catholic and frowned on divorce. So they didn't tell the family, they went to a priest on the sly to get an annulment, and they got married - big wedding.
I begged her to not lie to the family - to come clean. They were nearly 30 years old - old enough to have had a past. Plus so many people knew of her divorce - it was sure to come out at some point. Nothing to be ashamed of. She fluffed off my advice.
Fast forward 10 years and two children. Marriage is falling apart. Why? "I can't believe what a liar he is! He never showed this side of himself when we were dating!"
My response was an honest one. "Sure he did. In fact, the two of you lied to his family for years."
"That was different - we had to lie."
I said, "If they'll do it with you, they'll do it to you."
His family eventually found out about her divorce and blamed the lies on her. Who couldn't have seen that one coming?
People whose eyes linger on every attractive man or woman who passes them on the street? Are they "shopping" or merely admiring? No way to know for sure, but it's a red flag.
People tell who they are, whether it's too many stories that start with, "My friends and I were partying and..." (substance abuse) or the sweet suggestion: "Can you put on something else? I want you to look especially nice today. The blue dress is particularly lovely." (controlling) or "I'm not leaving a tip for that lousy service" (abusive and cheap), or "How nice that you got the big promotion you were up for. Oh, let me tell you about the great donuts Fred brought into work today! (narcissistic - bring the attention back to themselves), or "Gee, I'd love to help you with that but darn it, I'm just so busy" (cross this person off your list when thinking about who you can count on when you need a hand). And so forth.
Like everyone else, I've been fooled many times over the years in all sorts of relationships, but looking back the warning signs were always there. Every. Single. Time.
I just fluffed them off as isolated incidents without connecting the dots.