[Reallytrying]

The thing that made me sure was his rejection of his parenting role. He had always been such an active dad. Other than that:
1.  Anger phase - you've never done anything to make me happy. Which came not long after him telling me how much I meant to him and how he'd never want to lose me.
2.  Exercising all the time, lost lots of weight
3.  Partying constantly. Drinking way more than he ever had.
4.  Change in style of dress
5.  New friends
6.  Eyes that looked lifeless.
7.  New 2 door sports car

I'm sure a million more if I think about it some more.

[Cat66]

For me it was

Criticising me and making no effort in relationship (leading up to BD)
Walking away from marriage and 6 yr old daughter
Spending money like water without a care in the world
Drinking and partying heavily
Exercising and dieting, now in better shape than ever before, also runs marathons
New clothes
New friends
Lying
No period of grief for marriage breakdown
No empathy

I think most MLCers described could almost be the same person rolled into one 

[MyBrainIsBroken]

For me the clincher was when she walked away from GD14. The two of them were inseparable. It practically destroyed GD14. I wouldn't have believed anything could separate those two.

[heroIam]

OM,
I also inquired about this question many, many times.  But here's what I observed in my H if it helps.

No empathy
New clothes
New luxury car
Lying/Deceit/Secretive
Ambivalence/Confusion
Avoiding eye contact at times
Conflict avoider
OW
Addiction/Depression

[Thunder]

Ocean, it's all so black and white, isn't it?  Like they follow a script.

They just completely turn into someone else.
They do and say things we never imagined possible.

To me the one thing that seems to happen to all of them is they have this fierce need to "get in shape."
Like they NEED to find someone so badly they try to look the best they can to attract them.
Then it's new, younger clothes to go with the new body.

I don't know one of them who didn't do that.  Male or female.

[Beacon]

Overall just becoming a completely different person almost overnight...

A few key signs:
* Started staying away from home at days at a time saying she was "helping" friends
* Lying/being secretive
* Spending ridiculous amounts of money
* Started exercising but not really mostly just wearing exercise clothes and posting on FB about exercising but never did.
* Change in eating, over the top dieting.
* Completely disconnected from friends, family, and me of course.
* Avoided eye contact / Eyes look so empty
* Constantly talks about being old
* Never monstered but would say stuff like "You deserve better"

[Velika]

Ocean, I like your organized way of trying to understand. It helps a lot, I think.

This is what I have experienced:

Pre Bomb Drop (three years)

• Secret friendship with OW in another city.
• Periods of small outbursts and hostility I noticed as "out of character." Included driving fast when angry, making passive aggressive comments in public (twice), saying "f--- you" during an argument, and ripping off (own) clothing item during argument. Always apologized for these afterwards or initiated makeup.
• Intense period of fitness. Began to work out regularly and go for long runs. Lost a lot of weight.
• Watched a lot of Louis CK (who complains a lot about marriage), sudden obsession with boxing, watched a lot of documentaries about music and bands.
• Three years of intense work/work travel/job stress/success.
• Severe digestion problems.

Post Bomb Drop (eight months)

• "Devalue and Discard" phase. Immediately went from loving and affectionate to hostile and cruel.
• Refusal to take responsibility for own behavior, either contribution to marriage issues or behavior post bomb drop.
• Blame, anger, and projection toward me.
• General NPD traits.
• Multiple personality traits, including speaking in accent regional to his youth, different body language, sometimes talking like a little boy, other times yelling at me like a teenager. Sometimes slurs when angry.
• Lack of moral behavior. Lying to me, lying to son, gross behavior related to OW.
• Reconnection to old friends and family, especially to people he felt sorry for in the past.
• Odd choice of OW.
• "Shape shifting." His face and body often look different. Sometimes he looks like an old man, other times pudgy and burnt out.
• "Lifeless" eyes. Look like black dots on face.
• "Lifeless" skin contact. Feels cool and dead to the touch.
• Inconsistent behavior and statements. For example, after moving out, would suggest home improvement projects, will sometimes say "if we get divorced" and "when we get divorced" in the same conversation.
• Divorce and custody threats when angry.
• New hobbies. These include guitar, Bernie Sanders, and now drumming.
• New eating/drinking habits. Pre BD could not tolerate wine or coffee but drinks then regularly now.
• Change in dress and hair style. Possibly reflecting OW involvement/influence.
• Circular conversations and reasoning.
• Fantasy thinking. Thought we could be friends immediately after he left and even though he is treating me badly.
• Ability to project a mask to others but not to me.
• Lessened interest in son and dog. The few times he has seemed like his "old self" he immediately appeared to be trying to "reconnect" to the dog.
• Little interest in former friends; occasionally will make an effort but more to "show" he is fine, then immediately loses interest.
• Complete 180 on money/finances. Spends more money, less financially responsible.
• Connection to teen years and early twenties seems stronger than connection to his thirties. Reminds me of dementia.
• "Fight or flight" behavior, including hanging up on me, running away from me, acting panicked, threatening to call the cops.
• Mild paranoia.
• Ranting. By phone or text message; occasionally in person.
• Withdrawn/depressed behavior especially about five months post bomb drop.
• Memory gaps.
• Rewrites history, both of marriage and now even bomb drop and post bomb drop.

Ocean, I'm not sure if you have seen it but this is an excellent list of MLC behaviors and traits. Highly recommended to read:

http://whatismidlifecrisis.blogspot.co.uk/2013/07/signs-of-depression-in-mlc.html?m=1

[Cat66]

That's interesting Velika, my H now suffers from severe stomach upsets and frequent eye infections - not sure if there's a connection but he was a lot healthier Pre BD even though he is a lot fitter now.

[Velika]

Cat, I started this thread if you are interested. Since there is an increasing understanding of gut/brain connection I think this is relevant:

http://mlcforum.theherosspouse.com/index.php?topic=7306.0

[Cat66]

Thanks Velika, I will read with interest!