How do I deal with flirting...

[Corinthian44]

Recently went to my partners Christmas dinner dance ..observed a much younger colleague flirting with him.
I remember him telling me a year ago that she one said if she was 20 years older .. Shes been back from mat leave after being away about a year.
I know he likes her and I could see her watching him and as we left she made a point of telling him when she's me back at work after Christmas.
Do I mention my paranoia to him or not? I'm thinking I'd I do he'll stop talking to me about her.

From your post I can't see how she was flirting.
She may have been looking at him but that's it.
She's just had a baby so assuming she is in a committed relationship.
What are you worried about?
Do you trust your DP?
How long have you been with him?
Has he given you reason to doubt him before?

Hmmm you can kinda tell when someone looks in a certain way. Then there's the 'accidental' touching of hands when reaching for the same item, you don't do that unless you want contact.
No he's not done anything before but it'll be a massive ego boost.
I just feel threatened

Trust your gut op.

You only have to read relationships board for an hour for the amount of men cheating with much younger colleagues and yes to these 'd'h it's an irresistible ego boost.
You know him best and if you think bringing it up will make him talk less about it then that's exactly what he will do.
I'd advise keeping quiet but be alert to any changes in his habits.

I hope you have nothing to worry about op.

Thank you x
I know I have to trust him on this, he knows I'm vulnerable.
I'm sure he'd laugh and deny but if I brought it up it might highlight it, and I don't want to do that. It's just I think should I let him know what I observed?

The thing is, she/it isn't going to go away so I need to deal with it but I don't know how!
I'm thinking they are together most days so it'll drive me mad.

@definitelymaybe8 Maybe you've had a user name fail, but I think you should look into it.

Yep how strange!!

Wouldn't like it one bit but unless DH actually did something dodgy I wouldn't mention it. If he is encouraging it, step in

Definitely trust your gut