What I see is your torment. At the moment you are not even sure that you want a R with this man in the future. You are asking what things you should look for in order for you to persuade yourself that you should go for it.
Nobody can answer that. You have to feel it, know it and live it. Everything that you have posted says that you are not ready to begin piecing if it is on the table.
It's far too soon to talk about whether his changes are permanent. You know that; hence the torment.
You need time. Are you worried that this is a once only chance and if you don't grab it he will get pi**ed off?
If he's not prepared to give you ALL the time you need then that's your answer about permanent changes.
There's no need to force any time scale. Continue to be kind and true to yourself and sit back and see what ensues.
