Tell her to keep her hands to herself or you'll break her fingers

I’m the flip side of this. I’m married & have a single, older co worker who’s very touchy. Doesn’t worry me, we’re great friends & flirt outrageously which hubby knows. This male is known as my work hubby.
Don’t let it worry u

How well/long have they known each other? How well do you know her. I have a male best friend for 25 years. We are close and often touchy, hug, he even lays with his head in my lap at times. There has never been anything sexual or romantic between us. Both martied. Neither of our partners have an issue as we all have such a long history. He is one of my hubbys best mates and his wife is one of my best friends. If we didn't all have the history it would be different and if there was a woman that had a history with my husband that i barely knew Id have issues. We definitely have different boundaries with different people but our whole friendship group is pretty close

She has a partner she probably looks at him more like a brother then having any sexual interests in him.

You need to speak to your partner about it. Is he uncomfortable? Has he really noticed? Do they have a history? Did they grow up together like siblings?
Watch her behaviour with other men she's known a long time next time you're all out. Is it the same? Or is she singling out your partner?
I think you need to tell your partner it makes you uncomfortable and ask him to put a stop to it - easy enough to move away, take her arm and put it back, put you in between them, etc. or just say something like "Gee, Sandra, you're a bit handsy!"

When you are around her get all lovey and touchy feely with your husband and see how he reacts to you. If he pushes you aside or he makes you feel as if you should be else where bc he like the attention of the other lady maybe theres something elae going on!!!

Is she flirty or just touchy?
Have they been friends longer than he's known you? I agree with the territory thing. Some females are strange

I get it. It's inappropriate. If she does that he should move back from her.

She might just be stamping her territory.....i was here long before you & I'll be here long after your gone - bad boys for life

Let him know how you feel and ask him to ask her to stop. If he doesn’t do the same with some random male in the same group.

Not at all. Id be really pissed too if some other broad was flirting with my man. You say she's married but he's also in a relationship...with you. I think you need to deal with him allowing this to happen first. Good luck hun x