Yes, I caught up with your posts. YOU can do this, but you need to keep calm, no more panic attacks, just let him be. When you got involved with getting yourself to the gym, going out, doing things for you...you were doing great.
Now, you need to keep it a business relationship - he must not see you upset, sad, or asking questions. Let his affair end on its own time - there is absolutely nothing that you can do to end it, make it end any faster, or try to change his mind. Work on being that different woman - act like it doesn't bother you one ounce...let him wonder why you're not fighting, let him worry what has gotten into you...be the mysterious woman with no strings attached. He knows you, your reactions, your needs, you are predictible to him. When he can predict your every move then, there's no excitement for him - he needs to "miss" you, to long for you...but you are throwing yourself at him, that's not too appealing.
You can win him back...just cut him loose for now...worry only about the business end...no more tricks, questions, snooping, or trying to run into him...okay?