What you are going through is one of the most painful things you can experience. It is normal to feel a number of painful feelings quite strongly when your spouse has been with someone else. You feel angry, cheated, hurt, rejected, resentful and depressed. You want to trust her again but you can't seem to find a way to do it. You want her to acknowledge how much she has hurt you but you get excuses and accusations instead. You get tired of feeling all these strong feelings and just want to get over it and forgive and forget but you can't seem to let go of the pain and all the accompanying feelings mentioned above. You keep thinking about the affair even though you try not to. All of this is a normal reaction when you find out your spouse is having or had an affair.
She wants to believe you had an affair to justify her behavior. Don't argue with her about this.
Ask her what she would like from your marriage that she has not been getting and try really hard to listen with out being defensive and with out being overwhelmed and discouraged. If you get her talXXXXX, XXXXX't interrupt her, just listen, (you could even take some notes). If you are thinking to yourself "I can't believe she just said that, or, she should listen to herself talk sometime." just keep it to your self and keep listening.
It's not fair that you should have to be the listener when she owes you a huge and sincere apology but you have to check with your self on some thing, ask your self. "do I want to be right or do I want our marriage to have a chance to get well?"
This is pretty hard stuff to do all by your self. you may want to pick up a book on healing after an affair, or get some coaching or counseling. You can do all of the above even if she is not yet willing to.
Healing starts with you. Anything you do to become more well will add
to your future happiness. I hope she joins you but if not you still deserve to be well and happy.
P.S. It is possible for a marriage to heal even after an affair, many have.