Definitely-son needs honesty-because he's a person too.
But-I would make the effort to have the conversation together-all three of you. Not just you and him. He needs to hear his mom's words.
Also-keep in mind, that it's quite feasible she will want son with her part of the time once you are all in the same town again.
When we are working on issues within ourself-especially when we realize we are making progress, there is a temptation to jump on the "it's better now train".
IT's important to remember that currently you aren't dealing with the triggers that you had before when she was at home. That is going to make it easier to not behave in the same abusive manner. But-if you live together again-those triggers will return. I don't say this as a reason NOT to resume a full relationship. I say it as a word of warning.
Maca and I lived apart also. It WAS frustrating. I had the kids and little free time. He was lonely. It was tempting to cut short our separation because we did miss each other. But-we really needed that time to work on our individual shit and become STRONG in our new behaviors-strong enough to stick with them when the shit hit the fan (which is does and will).
You are working with the therapist-can I ask, have you asked the therapist what THEY think you are ready for?
I know in AA and the like-they suggest not resuming or starting a new relationship for at least a year. A friend of mine who has 20 years in the program says "not until you are solid through step 9-which could take several years".
You need to work on socializing. You keep bringing up the alone factor. YOU need to change that detail by going and making friends which CAN be done with a child in tow-I know because I have 4 children and helped raise 2 more, full time in my home. With 7 children in two, I managed to get out and socialize.
You won't be able to make the marriage work if you don't resolve that-because she isn't going to be with you 100% of the time ever again.
So-what do you need to help you with moving forward in that direction? I recently posted on here (in a different thread) a list of ideas for things to do with a young child to get you out of the doldrums of being stuck at home because another poster asked about it.
What would help YOU to do that?
(as for the thread-as the OP hasn't expressed any upset over this thread continuing I see no reason for any of us to. She said plenty clearly that she loves this man and wants to resolve things-but she was at a point where she needed to step away for her well-being. So I would think she would appreciate seeing that others are giving him advice that supports her needs-AND his.)
"Love As Thou Wilt"