WTH
All I can do is share how I IMAGINE I would handle a comparable situation.
First of all – I would make my disappointment very clear to my son. My kids joke about how I never get really angry and how they would have preferred that to how I get disappointed if they do something wrong. But… I would make it very clear to him that what he did with the EA was totally wrong, totally avoidable and he has NOTHING – NADA – ZILCH to explain, justify or in any way minimize the damage done.
I can imagine what he might say… Might talk about how there is not time for him after the baby came, no time for fun, no time for romance… yadayadayada.
Shut it off right away. This is life, this is what you signed up for when you married, when you decided (or accepted, or did not prevent it happening) to have kids…
I would then make it clear to him that you aren’t going to judge him on what he did, but more on how he handles it. If his wife wants out – then how he responds to that. What he does to save his family. What he does to make amends.
I would also make it very clear to him that falling on his own sword isn’t an option. Signing off all the marital assets and moving into his old bedroom is not an option.
Then I would ask him if he would be willing to sit down with me and his wife and have a talk about the possible next steps.
If he agrees… I would ask your DIL if she too would be willing to sit down with you.
Either both, or her first individually… but definitely so she hears it. Tell them that for NOW you are going to talk. They can get their words in later.
I would start by making my view on the son’s decision to have an affair very clear. Really lay into him once again. Share your past (briefly) and how you view infidelity.
I would mention that divorce is a very possible and likely outcome. If both are not willing to work HARD at fixing things, or one or both don’t want to be married then divorce is the only logical outcome.
I would then make divorce very clear: SHE doesn’t get to decide that she’s going to be a single mom and he get’s not custody. She won’t get the house, the cars, the child-support, the spousal-support… By default the law (generally) states that kids have a right to access both parents, and this divorce would start with a 50/50 custody schedule. Not been married long enough for spousal support to be high. Not many assets in the marriage, debt divided equally… Although none of these are great reasons to remain married they can be compelling reasons to try to remain married.
I would emphasize that this isn’t a situation that I want, but rather the reality of their situation.
I would suggest that at the very least they arrange some grace-period where they try to avoid the most harsh response to your son’s STUPID actions.
I would ask her what he would need to do to make her want to try.
I would ask if here was anything you or your wife could do to help. Take care of baby while they talk, let son sleep there to give her time…
I would suggest a couple of things:
I would suggest son works hard on realizing why he needed this external validation.
I would suggest they both read Not Just Friends by the late Dr Shirley Glass.
If I had the funds, I would offer to pay for some MC, but I would suggest they don’t go for maybe a couple of weeks.