I am 60 yo and have been with my partner for 40 years - we have 4 kids aged 27 to 33.
In 2012 i found out my partner was having an affair with a employee that was 20 years her junior. She was his boss. I would like to tell you that after nearly 10 years its gotten easier, however it hasnt ! quite possibly the reason it hasnt become easier is that i believe ( based on facts) that she still lies about exactly what happened.
I maybe in a different position to you and others in that - i have since 2012 studied behaviours and believe she is a complete narcissist and although after many discussions she says she sees how i think that she does not believe she is. it is easy to look up the term and take from it what you will to suit your circumstances but the reality is you either fit the criteria or you don't, please keep in mind there are many types of narcissists - grandiose, Vulnerable etc etc but nevertheless all are narcissists and they will always have trouble believing they are as typical of the NPD ( narcissistic personality disorder) that they are like this or have these disorders.
Whether or not we decide what or who they are is irrelevant to how they actually are or how they see themselves. In most if not all cases they can not ( unfortunately) change who they are - in nearly all case it is not fixable it can only be managed and then only if they can see who they are and candisplay the right amount of understanding and empathy which most lack altogether.
Having said the above - each circumstance of infidelity is generally different -
I struggle still with triggers on a daily basis, i have been counselled by 2 different (both females) phycologists about my issues with this - both with a combined 74 years experience and still cant get where i should be !!!!
I may add add at this point i have just today signed up with BB as another issue has just been raised and im at a point where ive had enough and wanted to seek help and then saw your post and felt compelled to contribute.
Make no mistake we and only we that have been and gone through this understand and thats why i was looking up support groups on this site but couldnt find what i was looking for.
I could spend hours on her telling you of my situation but i just wanted you to know i feel your pain and am here if you want to talk.
Take care Doc