How can I compete when the Other Woman (or Other Man) seems better than me?
You've got to be very careful here. It's only natural to compare yourself to your partner's lover in an attempt to understand WHY this happened, but the truth is you are not in competition with that person. The real competition here is between your partner's view of the affair relationship and his/her view of your marriage (or relationship). But the problem is that these views are inaccurate, even though your partner is convinced they are right.
An emotional shift has occurred. Everything your partner experiences in the affair is interpreted with a positive bias. It is a way of thinking that will not last, even though they are likely convinced it will. Alternatively, your partner's thoughts about your relationship are interpreted with an opposite, negative bias. Even their belief about the history of your marriage has likely changed in ways you hardly recognize. The real battle is between these two twisted views.
Focusing on how you compare to the affair partner will lead you toward confusion, frustration, despair, or obsession. Don't allow the affair to have that kind of power. While it is appropriate for you to consider the role you played in your relationship, don't use the affair partner as a standard by which you measure yourself. It's a broken yardstick.
Years ago, betrayed spouse responded to this very question in our online forum. This is her excellent response:
Any questions that form a comparison or a competition (Was sex better? Was she prettier, thinner, smarter, wealthier? Did you enjoy talking with her more? etc.) are not necessary, in my opinion. I know why we ask them. The affair wounds our self-worth. It takes over like a monster.
I'd like anyone feeling the pain of those questions to try this exercise: Write down all your spouse's positive points, attractions, and best qualities. Then consider them and ask yourself if no one else is as good or better than them in those areas. Chances are there are many people in the world, or even people you know, who are more attractive, thinner, wealthier, better at sex, smarter, or more interesting than your spouse. Do you think less of your spouse because so many people are better than them at those things? Probably not.
This isn't about putting down your wayward spouse. It's about realizing marriage isn't a competition. You didn't marry them because they were "the best." You chose them because you loved them. They didn't marry you because you were the best but because they loved you. They didn't cheat because you got older, softer, too familiar, or because they found something better, or because you were lacking anything. They cheated because of something lacking in themselves.
If [satisfaction in a relationship] is about finding something better, trust me, they will never find it. Real long-term love will elude them forever. There is always someone better at something. Someone will always be younger, more attractive, or more educated. That doesn't make YOU any less. Marriage isn't about trading up for bigger, better, and newer models.
I wondered for a long time if the sex was better with the affair partner. Then one day, I realized I could probably have better sex with someone else. I just didn't. There were many men more attractive than my husband. I just didn't care because I was married. There were men smarter or more educated than my husband. Does that mean my husband was less than other men? No. He was just him. And I married him. I wasn't faithful because he was the best at everything. I was faithful because I chose to be and because I wasn't lacking something inside me that I thought could be filled with something on the outside.
Don't demean your worth with comparison questions. If you compare yourself to others, you can always find yourself lacking something. You don't have to be the best; just be the best you. The best you is worthy of love and honesty and faithfulness, and so much more.