We’ve been together a year. Started casually but it’s grown steadily and we’re thinking about moving in together.
Very early on, he told me that he’d been having an affair with his mum’s friend but ended it soon after meeting me.
Apparently she was very upset but said she understood him wanting to be with someone more his age.
She’d been trying to put him off me before then, whispering in his ear that I wasn’t good enough for him, that I wouldn’t make him happy.
His mum has no idea. The friend made him promise not to tell her. But I feel uncomfortable knowing this secret. And it makes my blood boil every time she talks about her friend, what an angel she is and how kind she was to my partner when he was down in the dumps after losing his job.
Yeah, she was a fucking angel alright! 
For context she’s 46, 16 years older than my partner.
Whenever I see her she gives me the cold shoulder and makes pointed references to in-jokes that I am not part of. But always smiles and hugs me in front of others which drives me mad. They don’t see what a manipulative cow she really is.
The number of times I’ve had to bite my tongue whenever his Mum sings her praises, I have come so close to blurting it out. I know that if his mum ever knew, she’d be very upset.
WWYD?