Replying to this from the point of view of a friend who is in a similar situation with a man...
Her close friends and family are dearly concerned for her, but won't say as we don't want to be the ones to sh*t on her happiness. One friend already cut off who raised concern.
Dfriend is a very accomplished woman and has a phenomenal job, very financially sound, also lost her husband and received significant sums. Children and young adults now.
Her now fiancé came on the scene within a year or two, no assets of his own, not a penny to his name and was previously living with his mum after he apparently "gave" (bless) his house to his ex. It turned out later that it was actually never his house, it was given to her by family. She did give him 7k when he left which was generous. He bangs on about paying his exes mortgage but... as others have said... he would have had to pay rent somewhere else if he didn't live there... it does cost to have a roof over your head...
So anyway, he met my friend, moved in by sleath after a few short months. He's here all the time anyway she says.... seems a nice guy on face value, makes her happy.
But he pays nothing, no bills. Just does the occasional food shop and buys her flowers.
Put a ring on it after a year or so, paying the ring off on finance, still doesn't contribute to any bills. He's living completely for free. In a minimum wage job and he now lives in a lovely home with no bills to pay.
My friend has changed her will now, to leave him 30% and her children 70%.
Whoever did he will says as long as she leaves him reasonable provision, it should be fine and he shouldn't be able to claim any more. If she tried to leave everything to her kids at this point in time, he could potentially have a claim as she has been "keeping" him.
I'm not sure what happens if get married and have a long marriage, because I would have thought that then everything because shared assets (her assets!), so it may not be divided the way she thinks. Maybe her 30/70 split will just be for her half of everything? Aren't assets split 50/50 for marriage?
I'm not sure but I think it's something to think very carefully about OP. I worry my friends assets will go to a new partner of her finance one day if anything happens, and her children will miss out. She is too old to have any more children with her fiancé.
He also has his children so it means hers and her deceased husbands hard work and assets going down someone else's family line.