@Spikyseason I'm so sorry this happened to you. I'm 7 month from discovery and can relate very much to your emotions.
obviously you need to make your own decisions but what helped me was to be scientific about it. I read a lot about the psychology of cheating and what it does to the victims.
my conclusion is cheating is abuse. you can not cheat without gaslighting. and gaslighting is recognised as abuse. the is the deception that is needed to cheat that damages you so deeply. he is forcing a false reality on to you, which is hugely damaging to your emotional state and your psychological wellbeing.
I remember to feel constantly confused, and so very busy making sense of loose ends and found messages and proof of lies and more lies and believing him. What I see now, looking back, there was never any sense to see. he lied: all. the. time. looked me in the eye and lied, not just about the affair but the smallest things. it scrambles your head, your reality is up side down and you cant think clearly because you are trying to see reason where there is non.
It works in his favour because this kind of fundamental gas lighting is so destabilising you can not make big decisions (like that you would be better of divorcing him) no, instead you ponder over the meaning of a necklace.
It doesn't matter what it meant or he meant. because he is abusing you.
Psycholosit Dr. Omar Minwalla has some models around why sexual betrayal is indeed a domestic abuse issue. worth a google.
Money wise - my stbx pissed away the entire amount set aside for a home extension on hotels and flights for his affair. TAX was the explanation, which I so desperately wanted to believe.
I feel for you and the stage of fog you are in. I sincerely wish you to break free and see how utterly cruel he is and that a better world awaits without him.