Hi, I am 41 and I lived with my second boyfriend for quite a long time, maybe 4 years. Didn't think of it as "shacking up". I think you may be thinking of about 2 generations before you. Maybe someone who is 70 or 80 right now (I'm thinking of my own very conservative parents. My parents were in their 30's when they had children). I have been married for almost 11 years to the third boyfriend and have had two children with him. It has not been easy, but for some crazy reason, it's better now than it ever has been. I highly recommend couple, single and group therapy, self help books, transformation courses, any kind of education to get you through the challenges. I think you must be willing to introspect and work on yourself to make your marriage and your relationship with your children to be satisfying. Unless you were fortunate enough to have come from a really happy, functional family already and all those behaviors and ways of being are already second nature for you.