thegoodgirl...
I feel so bad for you for going through this difficult time. I think there is very little that any of us can do to help you find out FOR SURE if your husband is cheating on you. (aside from you buying a ticket and spying on them, or hiring a private detective in that area to find out on your behalf). But is that really necessary?!
You feel suspicious and betrayed (and I feel appropriately so!). Perhaps a few objective words from someone that is a complete 'outsider'. (and a person that has gone through a huge betrayal by my first wife... and a painful and expensive divorce)
"IF" your husband has found it appropriate or necessary to cheat on you... this says more about HIM than it does you! I know this will be one of the hardest things to accept - but it is true. It will have been his character that is lacking, not yours. Smile... you are the person that has character that holds strong even when tempted by another. "IF" your husband has found it impossible to hold true to your marriage... then it just shows that you had different values on this relationship. It hurts to acknowledge... but it is an objective truth.
Someone told me once: "Life is not a dress rehearsal". With this in mind, "IF" your husband has found that an affair or 'one-night-stand' is more important to him than a solid marriage with a life partner, then, it may be appropriate to smile and accept that. YOU will have learned about his priorities in life, and you both will have deserved better: You deserve a person with a firm resolve to hold to something bigger than an evening with emotionless sensation... and he deserves the life and disappointment that comes with a teenager's partying lifestyle (or the life that comes with this other woman. He only has one chance at his life - remember? He is abligated to find what makes him happy. You can't fight that.)
It is a powerful statement to a man - when you, the person that he betrayed, approaches his infidelity with a mature, centered, unemotional response... that reflects how immature his choices have been. Can he win you back? That is only for YOU to decide. (although I have strong reservations on believing that the trust could ever be truly rebuilt. And 'trust' is critical to any peaceful relationship.)
So...thegoodgirl... now it's up to you. What do YOU want from your relationship? Remove the image of your husband from your mind and write it down. Be objective and true to yourself. Once it is written down, ask yourself if you believe that your husband fills that role. (Your husband may have done this exercise already without you even knowing it - and that might be the reason why this situation with this other woman has happened)
If he doesn't fit that role.... then I ask you to consider: "Life is not a dress rehearsal".
I wish you the ability to find the inner peace to sort through this nightmare. I know it won't be easy. Additionally, in response to your comment that you are shaking... I strongly encourage you to see your doctor and see if he will prescribe something like Xanax or something that will diminish your anxiety level. I have been there.
Take care...
NOdenial