I agree with onandup. Don't beat yourself up. It won't help you, or him, or your DP. Focusing your thoughts and energy on feeling guilty will divert them from where they are really needed.
Mabel, many of us who have posted on this thread have been in similar situations to you. Like onandup, I've been there - had that ecstatic rush of feelings when someone has made contact who you thought you might never hear from again. So I am not going to call you names. And I don't think you should be calling yourself names either.
These feelings, urges to contact him, feelings of pain are to be expected. They are part of the script, the pattern - so you need to draw on some other source of strength at those times. A source of strength that isn't emotional.
By sending you that text yesterday, OM showed that he is not willing/strong enough to help you to maintain the no-contact plan. He is not a source of strength for you in this respect.
I'm not apportioning blame here - it isn't about blame. The fact that you texted first is irrelevant for this point. He has shown again and again that he is not going to help you to maintain no contact.
He is not on the side of making your life easier.
He is not on the side of you saving your relationship with DP.
Again, I reiterate, I am not making any judgements about OM - I am simply trying to state the facts.
You said that you can't bear to go back to square one by seeing him again. But actually square one is where you are anyway - you are going to have to start the whole process of no contact again. Seeing him again won't take you back to square one. It'll take you somewhere new and potentially very dangerous indeed. It won't be like it has been before. There is a whole new layer of emotion and pressure on meeting up now.
You ARE amazing, Mabel. I am not going to take it back. I think you have questioned yourself and tried and battled really really hard, and you have had insights into yourself and your relationship with DP that have really made you think. I think you have a great capacity for honesty with yourself, and I think that is what you have to draw on now.
Forget about relying on your feelings or taking them into account with regard to OM. Your feelings are all over the place and they will not guide you well. Trust in your own personal sense of right and wrong. Put your back up against that. Don't even consult your feelings.
What is the RIGHT thing to do?
You said "There were so many unanswered questions from our last, final meeting...I want to comfort myself with getting some answers." You are not seeing objectively right now, but please listen to all the people on here who have been there too.
There will NEVER be a point where you can have a final meeting with him, get all your questions answered, shake hands and say goodbye and feel that you have drawn a clean line under it. It will not happen. Each new meeting will throw up more questions, worries, thoughts.
And even if by some miracle you were able to shake hands and say goodbye and feel at peace, the following day or week or month there would be a story in the news that you wanted to share with him, or some event that you knew he would be watching. And you would have the urge to call him or text him, and it would all start again.
You know from reading MN that an emotional affair is often as powerful and damaging as a physical one. Therefore, the idea that you can meet him again without taking it further is an oxymoron. Just by meeting him again, you ARE taking the emotional affair further.
Just try to focus on what you think (not feel) is the right thing to do. And then do it.
You've discussed before how this is really inextricably linked to your relationship with DP and his behaviour. That is still the issue that needs attention and work.
Right now, you are standing at a crossroads. If you 100% want to give your relationship with DP your best shot, you will not meet up or make contact with OM again. Easier said than done of course, but it's a fairly straightforward conclusion.
If actually your feelings about OM come first, then listen to what you are telling yourself. It would suggest to me that your real message is that you are not prepared to battle to save things with DP any more. Having heard what you have been through with him, I would understand that. But he would deserve to be told, so that you could both start to build new lives.
You are your own support - you are the person you have to rely on to take you forward to a happier way of life. So listen to that woman. Be honest with her. And do what is best for her (and those she loves, of course).
Sending you lots of support and encouragement. Keep posting if it helps. We are here and listening and ready to order you to sit on your hands and stop texting him!