I feel your pain OP, my father is exactly the same. 3 days safer my mother died his ‘friend’ called by to pay her respects. 3 weeks later they met for drinks, 6 weeks later they had a weekend away together and 4 months later he moved her in.
Me and my brother we so shocked, angry, grieving, the pain, I’ve never felt anything like it in my life. I found it hard to accept the woman and remained cool with her.
My father became annoyed that we weren’t all over her with undying devotion and welcome, she was in the background dripping poison into the situation as she clearly felt my father and I were too close (I helped him lots with admin etc). She felt it was her place to then step into any role like that.
I could see it coming and various arguments were created by her when I asked to see my father alone etc.
Long story short he told me that if I didn’t fully accept her and treat her like a loved member of the family he wanted nothing to do with me.
So, I wasn’t prepared to be dictated to - the woman was little more than a stranger to me, I never spoke to him again. The hardest thing I ever did but you know, it’s his loss, he’s lost contact with his only two grandchildren (however he’s inherited a load of hers who have overtaken his house and drive him mad as I’ve heard through the grapevine). He’s been financially taken for a ride by her, he’s signed over half his house etc despite the fact she won’t marry him.
Any man that can be so self centred and thoughtless toward their children, no matter what the age they are, don’t deserve any thought or approval. I have no problem with people moving on after a period of time and first sounding out the feelings of their children etc but to jump straight in, I have no idea how they can even do that??
If my husband died I’d be sickened at the thought of another man that soon, why would you even want to??