you are weak, you allow every woman you love to destroy you easily. you should be stronger than that. and it wont make you a worst lover.
your worst fears in love is being cheated on. 
or imagining your mate in the arm of another male
While you can imagine her making out with a girl (doublestandar)
In fact you didnt really liked seeing your girl making out with another.
This is how you end up thinking you were mono.

First cheat story that affected you: (childhood imaginary)
imaginary girlfriend who restarted a life with you child with another man. who is nice
The hero stalked and fell into a spiral of alienation. But he wasnt mad at her, he just wanted her back.

You cheated on julie while she was at mtl. you kissed another girl several time and hoped something of it.
You were just affraid. she cried watching the stream when she learned.
Though I still had lot of fun with her later.

I got dumped for another dude by an highschool girl,
was limerent. They kissed, it wasnt so bad, but getting dumped hurt like a shovel in my hearth.
6 month of grief, and lot a hatred.

Myelle cheated on me in 97
litterally slept with another boy while i was waiting for her.
I hated her. Shame. discust. Still I wanted her to stay with me.

M-P humiliated me a lot.
But I didnt understand that she was poly and just didnt understand how it was different for me.
We both tried to impose a relationship scheme on the other.

When I watch a movie about infidelity, it stress me a lot.

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first thing, the dick brother
I have dick brother. a lot.
I shouldn mind having another.
Unless std.
For the same reason i dont drink in anyglass or dont smoke joint, i am discuted of someone else saliva.
Once I exchange fluid with another girl it mean a lot for me. And I dont want to have other dude fluid mixed in her.
(strtegy aply here, she get a shower and you make her love sooner the better)
You should be able to accept contact with foregner. At least overwelm them in her.

Shame
You feel humiliated because someone oozed something important for you.
Hehe she yours, she is mine. Not necessary, she could want to stay with you, mean you lost nothing.
Feel that you are not enough for her. The truth she is not enough for you. 
You dont cheat because you are empathic and respect full, she cheated because she was selfish.

loss
same thing, you dont necessary lost her, unless she was openly tired of you, it would be a rude way to deal with the problem.
But if she want to keep you, she is still there. She just messed her vagina stupidly.
You still feel that you lost her, of course, you subconscious now reject her because she is a whore, but your hearth still love her.
(you will certainly know if you loosed her by fucking her right on the spot she told you, like fucked the feeling memory of that day)

deception
you are allowed to be decieved, but not to revenge. She dont owe you to be cheated.
She was not up to the expectation. Take a deep breath and stop expect thing about her without first talking about it.

jalousy
The most painfull part, seing a rival enjoy and waste a thing you cherish. And now it nothing.
First you dont own her body. If she let touch her body, it has nothing todo with you. She is just unfaithfull.
You dont have to compare yourself to him, he didint got her because he was better.
You were the most faithfull. She was the selfish, he was the opportunist, and he clearly lack self care putting his dick in your juice.

Foremost, you dont have to accept that this will destroy you. It shouldnt.
If she dont want to return to you, then the story ended a while ago.
If she return to you then make sure she remember who is the real man.
If she want to keep both, talk about polyamorous relationship and BOUNDARY!!!! and open your hearth


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you have to understand your marriage like it really was. not how you wanted it.
your wife was not faithfull. but really loved you.
you were not totally faithfull
but always prioritise her.

there is nothibg pure. and was lot of work.