In my opinion, you are doing the right thing by staying on the sidelines… for now.
However… as human beings, we need understanding and love, as do we need to give them. Be there for your Fiancé (or is it ‘Friend’ at this point) to help him with his ‘journey’ if he reaches out to you. You obviously love each other, as you were to be married. My ex wife (separated, however still married on paper) and I are still very good friends and confidants. I don’t know what I’d do without her.
From what I have read online, many CD’s have ‘desires’ for men when they are dressed. So it doesn’t surprise me that your Fiancé visited a gay dating website. As you mentioned, you can’t tolerate this behavior. I 100% agree with you… It’s cheating.
He Will Not Change. He may promise you that he will, but the ‘Urge’ is very powerfull (gets stronger as the years go by) and eventually he will fall back into old habits. He is who he is… you will not be able to change him.
Time will heal your emotional wounds… when you are feeling better, reach out to him and offer your support… He will Love you for that I’m sure.
Huggs and Kisses…