Congrats on working on your attachment style. So many people don’t realize the impact attachment has on one’s relationship and taking time to address attachment issues is important.
It’s also great that you are approaching the betrayal with a positive attitude. Research shows that people who engage in “benefit finding” come through all sorts of trying experiences with better outcomes. In fact, all relationships (and life in general) can be seen as a series of setbacks. What matters the most is not whether setbacks happen (they ALWAYS will), but how people cope with the setbacks they experience. If you and your wife are willing to work on problems together that’s a great sign.
As to your question: Is it normal to beat yourself up for the role you may have played in your wife’s infidelity? My guess is that you’re beating yourself up due to your attachment style. If you have concerned/anxious tendencies or you identified as having a strong anxious style in the past, it’s normal for someone to revert back to past coping strategies when something traumatic happens. People who have concerned/anxious tendencies are more likely to beat themselves up when their partners do something wrong. They see how their actions may have contributed to the problem and they blame themselves (to some extent) for what happened. For the most part, this isn’t a useful coping strategy. The problem is that feelings of shame — viewing one’s self negatively — doesn’t help couples solve problems and it often leads to rumination, negativity, and sadness. A better approach is to acknowledge that some of your behaviors may have contributed to your wife’s actions, but don’t beat yourself up over it. Acknowledge it, accept it, and treat yourself with love and kindness. Yes, you may have made some mistakes, but EVERYONE has. Making mistakes is a part of life. Reflect (rather than ruminate) on your mistakes. Acknowledge that your BEHAVIOR (not YOU) may have been somewhat problematic. Again, treat yourself with kindness and compassion. Forgive yourself for the mistakes you might have made. It’s OK. Focus on doing better in the future. Confident (secure) individuals acknowledge their mistakes, treat themselves with kindness, and take steps to change their behavior. I suspect the more you treat yourself with compassion and kindness, the easier it will be to work through this issue.
Hope this helps!