Hi Scrant, sorry to be late to the party! I think your reply was fine. Best to always aim for brief, pleasant, firm I think. Again, this all comes back to the fundamental question - you decided to leave our M for an OP and I am trying to rebuild my life. Why would I want to have dinner with you?
I'm not saying you should say any of this - merely that it's what your non-acceptance conveys. Or it conveys that you are just busy that day with other commitments - of course they will remain mysterious. If you W does ask you what you're doing, I always think it is good to give some partial information - Oh, I'm going to Nashville that day. This leaves an image in the mind and lots of unanswered questions - who with, to do what? etc. Better than just saying 'I already have plans.'
I think you are doing well so early in the process. Many posters are so consumed by fear at this stage, they will accept invites just to have the reassurance of time with their W - but I don't believe that is the best way.
Take care xx
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus