Guilt is a healthy response as a reaction to the past, yet it is a dysfunctional response to our posture for the future. If the guilt is undermining your confidence in your ability to move forward in your life, it is a really bad thing.
Experiencing guilt and shame means identifying what psychologists call an “internal locus of control,” namely that while we do not control all our circumstances, we have agency over the important choices in our lives. Shame and guilt are therefore profoundly empowering. They are an affirmation that we are not powerless about what decisions we make or what happens to us. We accept responsibility, because we believe we are largely in control of our destinies.
Accepting responsibility also allows us to decide that on a new path going forward. Only people who believe themselves to be powerless about past actions have reason to be insecure about their choices going forward.
It may feel cathartic to reveal all one’s past misdeeds to one’s romantic partner, but this is sometimes harmful and unnecessary. Share what you wish because it will be good for the relationship, not out of a desire to expiate your guilt.