There’s one thing men are extremely sensitive about.

Their hair.

I know this because when I first started dating my husband, I noticed a balding patch on the back of his head. Not thinking much of it, I commented on it, rubbing the spot affectionately.

“That’s not a bald patch,” he said. “I fell off my bike when I was a teenager and scraped my head on the road.”

Defensive much?

I suppose we would be the same if our hair was thinning. In fact many women do experience thinning hair as they age so be careful what you say about a man’s hair.

Hair kahma will come and get you!

MM Confessions: Relationship deal breakers. Article continues after this video.

But this is less about the actual hair, and more about the rules of a relationship.

When your partner is losing hair, do you tell them? Maybe it depends how much they’ve annoyed you that day. Perhaps you can store it up for a day when he makes a negative comment about your body –  if he would ever dare.

I think, as with all comments about your partner, talking to them about something delicate is all about how you say it.

I asked a bunch of women if they would ever tell their partners they were going bald and the answer was a resounding yes, but some of their methods for communicating this potentially devastating information are pretty clever.

Some prefer the indirect route:

Take a photo of the back of them and let him find out for himself. Oh look at the beautiful sunset. Go stand there and I’ll take a photo…S

Then there are those who prefer to just blurt it out:

I commented on his beard being a lot shorter in the middle and he was like a wounded puppy dog. I don’t think he’s forgiven me yet. R

And some who prefer not to say anything, unless specifically asked:

What if they show you and ask you directly if you think they are thinning and they are. Can you say, 'Yeah, but so what?' Like it's no big deal? J

Others are grateful that clippers have become the must-have item of balding men.

My husband is losing his hair and it's happened quite suddenly, but when the time comes he's going to shave it all off. He already has a plan.

Unfortunately, unlike with weight, there's not much a man can do about losing his hair, aside from crossing their fingers, increasing their vitamin intake or getting some sort of cosmetic treatment.

And it's not like they can blame their mother's father anymore. That particular genetic myth has been busted, with the most recent studies finding that it's genes from both parents that contribute to a man's chances of losing his hair, according to WebMD.

Perhaps just buy him a lovely hat, or comment that you find balding men sexy, but be casual about it - and remind him you love him no matter what. Because don't you?

We are all going to change, and don't you expect him to love you through thick and thin?

However you handle your partner's hairline and your feelings towards it, remember he will probably have a lot of emotions (even if he pretends otherwise) about it.

As the Greek philosopher Heraclitus (who appears to have favoured a combover) said: "The only thing that is constant is change."

Nothing, not even hairlines, are a certainty.

Sunrise presenter Edwina Bartholomew on realising work was interfering with her love life. Article continues after this podcast clip.

Would you tell your partner that he was going bald? Answer in the Comments section below.