I don't know what to do

It may be the wrong thing but personally I wouldn’t be able to keep something so huge to myself. I would either challenge him first and tell him he needed to own it or just tell my daughter.

This is obviously the least important thing here, but it is not illegal to be on the electoral roll at two addresses as long as you don't vote twice.

I do feel for you, what a shock you have had. If you have only just found out I would use a few days to think about it before taking any action, you are in shock at the moment and will need a bit of time to process this information.

I’d challenge him first, if he won’t own it then I’d tell your daughter.

Definitely don't say anything just now until you have thought about it. You could contact your son in law, let him know that you have this information and give him a week to tell your daughter himself or you will. I am just concerned that if you tell your daughter then it will irrevocably ruin the relationship you have with her at a time when she's going to need you.
How sure are you of the facts? It would be horrible if you had got the wrong end of the story and blundered in making accusations. You are in a very difficult position. I don't envy you.

Oh, my - please don't go to your son-in-law before talking to you daughter. Your daughter deserves that conversation before your son-in-law can hide assets, cover his undeserving arse!

More as I think of it.

Does your husband know? Are you bearing this all on your own? You say this horrid man (sorry, I have history) is "one" of your sons-in-law, so you have other daughters. Do any of your other daughter(s) have a good relationship with your hard-done-by daughter, and might know? Again, don't tell anyone before you tell your daughter - she's facing enough betrayal from her husband as it is. The idea of chatter about her behind her back would be awful.

I think this needs a face to face with your daughter, not a phone call, not a letter. Can you do a walk in the park and have a calm talk - no accusations , but armed with facts? And a flask of strong sweet tea just in case?

You may well become the villain if you approach either of them, I have no idea how I would handle such a nightmare situation. I can only wish you luck.

We had this happen in our family but it was the wife who found out. It was my OHs brother who was leading a double life.
She asked my OH and another brother to go to the woman’s house to confront him.
I couldn’t for one moment keep that information from my own daughter.

Thank you so much for your replies. It's helped just writing it here. I am 100% sure of my facts. I found the address from the electoral register and my son-in-law was supposedly working away. I took a trip and saw his car outside the house. I parked up and waited. They came out and walked down the street. I recognised both of them.

My husband knows as I was so upset I couldn't hide it from him. He fears that if we interfere we may cause more harm than good. At least the children have a part-time father. What worries me is how my daughter would feel if she found out that I knew and hadn't told her. She'd never forgive me. I have three other children but cannot bring myself to tell them.

Does he have other children aswell?

I think I'd try to help your daughter get her finances in order, if you've given them 100k you need to secure the housing for investment and your daughter and grandchildren.

I don't know what you can do on an emotional level but none of this is yours or your daughters fault

Gingerbeer I'm sorry, I don't have any advice to offer in this complex situation, but I would hesitate - if I were you - to write so much detail about a very personal issue on a public forum.

Anyone can read these threads, there is a Gransnet public Facebook page, sometimes links to discussions on here are posted there. I'm just saying, be careful how much you give away in the detail.

I wish you all the best.

1. Your daughter knows. She may not want to admit it to herself or to you, but she knows

2. 100k pounds for their house? Stop enabling.
It is not up to you provide for your daughter, she is an adult

3. His double life is none of your business.
Do nothing. Say nothing. Hint nothing.
Your daughter chooses to be married to him. She chooses her life.
Please dont meddle

i wonder if the other woman knows.
maybe he told her he'd divorced.
maybe he is a bigamist.

can you ask for your money back, if the extension isn't done.
never lend/give money like this.
best to be involved contractually with the builder, and research them carefully, so you know where the money goes.

seems like you have unwittingly been subsidising his other household.

i wonder why he would risk putting his name on the electoral roll at the other house, unless the woman there thinks it's his only home.
esp being in the same area.

You need to be very sure of your facts and then if you are 100% correct you need to tell your daughter, before she finds out that you knew.

I’m sorry but I don’t understand why you didn’t confront your SIL when he was with this other woman and then go straight over and tell your daughter.

I suspect that your daughter knows about his other life , and for reasons best known to her she is living with the situation.

This is a huge dilemma and I m not at all sure how I would handle it I only know if I was the wife ( your daughter) and everyone else knew and I didn’t I would feel SO, SO betrayed by you all
I m still trying to pick my jaw up that you gave them £100,000 just like that, bit by bit maybe, but just hand so much money over sounds very ott and why wasn’t he challenged when nothing was done to the house (not sure I understand why daughter and child lived with you for a year)

All I know is you can’t do ‘nothing’ now, so much is obvious and out there As he put his name on the electoral roll (perhaps she filled it in believing she’s the only one) it wouldn’t surprise me if he isn’t a bigamist if his name is at this other address for 10 years is this the same woman from work that you were suspicious of years ago ?
He sounds a real star she’d be better off without a man that spends no time at home, spends his in laws very generous monetary gift on other things, cancels holidays, doesn’t spend time with his kids and lives a double life and you say you love him I wouldn’t invest my love on such an arxxxxxle

(By the way your remark about beauty and plainness is ridiculous)

I think your son in law is leading a double life; living part time with both women. Does the 'other woman' have the same name as him on the electoral register? If so it's possible he may've married her bigamously, although I imagine that's harder to do these days; than in the past.

If I was in your daughter's position I would want to know and if I found out, that other people knew, especially when that other person was my mother, I would feel doubly deceived, but that's me.

I’m afraid I’d want the truth out there. If I were in your daughters shoes I’d feel betrayed by you too if you kept it from me. However, she may well already know ?‍♀️
But because you now also do I feel you are morally obligated.
I feel terribly sorry for you all in this situation but can’t see that it’s fair to allow it to carry on and it might take a more experienced advisor than folk here .....

You could also check Companies House for details of his business. You might find the other woman is part of it.

How can you be sure that your daughter is No1 wife and not No2 ?