Maybe rather then putting W on the spot about moving just assume she may go and let the whole thing go. Tell your S he has conveyed his feelings, and that's good. Now let her marinate with that. When you have a date, calmly let her know when it is. Act and talk like she will be going, but know inside and remind the boys she may not. You all will be allowing her to make her own decision. No pressure. It has to be her choice. But try to be positive. If she doesn't go explain that she's confused and needs to stay and live alone for awhile to figure things out.

I think the picnic should have been her choice too. Wasn't it your family? Perhaps she doesn't feel completely comfortable around them. It has taken me awhile to "warm up" to my H's family again (and I was the LBS!). Before all this how was the relationship with your wife and your family? Were they close?

Also, try not to dwell on that past stuff about OM. I know how upsetting it is. There was a time my H said and did things that made me (and the kids) swear that some alien being somehow evicted him and got into his body.

There is no arriving, ever. It is all a continual becoming.