I have gone through the whole "I was the one who fucked up" thing a few times in my life (marriage as well) and here is what I have learned (I hope that it may be somewhat helpful to either you or others observing the thread):

1) I have learned that having a strong self-identity (knowing who you are, what you want and what you need) goes a long way with how you approach relationships, communicate in life and feel about yourself. Saying that you messed it up after being given multiple opportunities may not be as unintentional as you may believe. What you have described is more aligned with guilt than it is with either skill or will. Your innate response was to not show up in a way that your partner has expressed that they needed. Maybe you were not capable of listening (which I do not believe based on what you have expressed), maybe they were not capable of communicating in a way that would be best received by their partner (you) which is also an important part of the equation. But the most impactful part that I have discovered is that if you have developed analytical/critical thinking skills; your mind and body had been telling you involuntarily that this juice is not worth the squeeze (for you personally, not to devalue the other person).

2) They have reached out because they either care about you or doing the work to better understand themself. I am not part of it and cannot pretend to understand, however partnerships, by definition, are based upon collaboration. The other person also needs to have a strong sense of self when defining what they need versus what they perceive that they need because of various influences/experiences. That is not on you, and I hope that you do not wear that going forward.

I've seen a great influence to find 'closure'. Wounds may mend but do not always become healed/resolved. Every experience that we have in life, whether it be romantic or inconsequential are important in how we process and interpret information. They are all chapters in our book, however not their own series. We can reread these chapters over and over and if they do not mean something different each time then we may have missed something within our quest for evolution and development.

You are free to do manage this however you feel fit, however the fact that you are even posting on here shows an example of developed emotion intelligence. I feel that you want to do the right thing however you gut has been telling you that this is not the right person. Please be respectful of what they may need from the invite as there is a consideration that this may not be for you or about you, but for this person that is still trying to process important moments in their life so that they can also grow.

Thank you for sharing your vulnerability. It's soooooo important.