His need for some time to sort things out is reasonable (considering the stress a divorce places on someone)
His statement that he does not know if he wants to be in a relationship is somewhat odd. He was already in a relationship with you. Perhaps he feels burned out from the whole divorce ordeal and thinks that getting closer to you would result in another disappointment.
Let him know that you would like to explore your options, you're willing to take things at the pace that he is comfortable with at this time. Point out to him the things that made you both happy during the last 8 months and ask him why would he want to give that up?
It seems that he is afraid of another commitment (the two of you do not have to rush into anything) so maybe you putting it to him this way could let him see the logic of giving the relationship a chance. Try to find out what his short term prospects are of the relationship (where does he see it going in the next 6 mo-1 year)