Three months is not that long relative to the time you guys were married. I truly understand the agony you must be going through. You may want to hold on for just a little while longer to see how things unfold, but hold on loosely. Meaning, Scale back on the amount of communication and contact that you have with her as much as you can. In the meantime, take care of yourself. . Get some hobbies or do something that you like to do. Start to slowly carve out your own life now. Join a singles group and take some fun trips etc. Sometimes people take for granted what they know they can have. In your case, your W probably knows that you are there when or if she is ready to come back. This makes it very easy for her to continue to see him without really having to make a "real" life changing decision... You think? It probably won't be until she sees you taking care of yourself, enjoying life and possibly moving on, will she be able to really understand the gravity of what she is doing and the decision(s) facing her. It's sort of human nature... unfortunately.

I hope I'm not being too nosey, but you mentioned that while trying to work things out with her, you would fall into a depression...unknowingly. Have you been able to evaluate what it is about you, her or the relationship that makes you depressed?