We're hitting milestones in our 40s now and some of my friends have been married for a long time.

I was married for a long time too, but, in the end, I left.

Since I left, my friends have started telling me secrets about their marriages.

Some of them are married to " good men". Some of them are married to "bad men".

Some of them are grieving a life that they aren't getting to live.

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I used to think when my husband died I would be happy. I would fantasise about a life without him.

Mostly those fantasies just involved me and my kids living happily ever after with the family pets — and not getting yelled at — but, sometimes, those fantasies involved me exploring my sexuality and being with a woman.

I feel extremely lucky that I didn't wait for my husband to die before I decided to pursue that alternative life. That parallel universe.

But I'm grateful too, that my husband was, in many ways, easy to leave because he did a lot of things that categorically put him into the "you really must leave" type of man.

With "good men" it's not so simple.

For my friends who are with men who are "good men", it's not so simple is it?

You know what a good man is. Men who help with the kids and the housework. Who don't yell or cheat or drink too much. Men who have good jobs and mow the lawns and hang up pictures and take the kids to soccer on a Saturday afternoon.

You don't leave a good man, right? That's absolutely something people have said to me, directly or indirectly, since I was a little girl.

But my friends who are married to good men are telling me things.

They've fallen in love, with people who they aren't married to.

They wonder if they are gay.

The sex isn't good. Maybe it's "just fine", maybe it's awful.

Sometimes my friendswhisper to me that their husband's bodies have changed — and they can't stand the thought of having sex with them anymore.

They have crushes on dads at school drop off or their personal trainers.

They just want someone they can go to a concert with and dance and make out with afterwards. But their husbands aren't the dancing type. Or the making out type either.

They want someone who books a babysitter and takes them out for dinner without being asked.

Someone who says, "Hey, lets go on a holiday, just the two of us. I'll book it."

Someone who is deeply interested in their thoughts and dreams and doesn't just see them as a wife and mother.

'Every conversation feels tense.'

Sometimes their beliefs have gone so far in the opposite direction to their partners, that they no longer believe in the same religion or politics, and it's hard to really see each other's perspectves. It feels like there's a chasm between them and every conversation feels tense.

Their husbands are good men, but something is missing. Something romantic, something about being truly seen and truly loved.

They think they will maybe get to be happy when their kids are grown up.

One friend texted me last week, "maybe when I'm old I'll get to be happy."

Leaving a marriage is hard. I know. I've done it, and it's hands down the most stressful experience I've ever been through.

It must be even harder for people who just, aren't in love anymore. Or who don't feel like their partners are in love with them anymore either.

Those who want to be in love with someone again and have tried " bringback the spark" courses and thought about open marriages.

Those that just can't bring themselves to think about living the next 20, 30 or 40 years with this low-level dissatisfaction humming through their days.

Thinking after every disappointing birthday or Mother's Day, that they definitely should leave, and then thinking the next day, that maybe they are being ridiculous and this is just normal, marriage is hard work, after all.

I think a lot of men feel like if they are ticking the boxes of being a "good man", they're safe.

I think men have a lower bar of what they need in a marriage. I'm sure there are a lot of men also lying awake thinking about a parallel universe too, but I suspect it's more women than men.

I heard that the majority of divorces are initiated by women and I believe it.

But how do we really figure out what is a deep dissatisfaction with the entire fabric of our marriage and what is just normal, after 20 years together?

Is it normal to be restless most days after being married for so long?

I don't know, honestly.

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What if what we are calling selfish is actually women just being honest with themselves, and with each other, instead of whispering these secrets over a few too many glasses of wine?

Women being honest that the life they thought they were buying into is not the life they ended up with.

Many of my friends found their partners before they were 25. Why is it shameful to say that the person you got together with when you were 19, is not the same person you want to be with now?

That you have changed, and they have changed, and there's another life you could live if you weren't with this person. It might be a better life. It might be better for your husband too — don't we all deserve to be loved deepy?

I'd never tell anyone to leave their marriage, but if you're waiting for your husband to die, or for you

to be old so you can finally be happy, I think maybe the cost of staying married might be too much.

Feature Image: Getty. (Stock image for illustrative purposes).