Love / Polish male partner's Vile female colleague [7]

i am engaged to a polish is man every thing is good apart from his awful female colleague.
Most of the women i have met are nice and I am very friendly with one in particular 'M'.
M's partner is a close friend of my fiance. The big problem is my finance's collegue Dorrie.
Ever since my fiance and I met she has caused problems, she cast doubts on whether i
really had the scientific job i have (it's a good one but poorly paid). she accused me of
being dirty in the house ( not entirely true though domestic stuff does not interest me.)
She comments about the fact that I my mother is jewish and a whole host of other things
if I go to see friends she implies I'm seeing a man. She has accused my friend M of stealing from her and trying to steal her

boyfriend (trust me no woman would, he's a nice person but an alcoholic and really not handsome).
I know two english men who have slept with her ( it's a small town) since she has been with her boyfriend.
She is also leading on some poor older guy, getting lifts to work and days out from him (he pays ) then complaining he wan'ts sex with her.

If she comes to any social events she flirts outrageously with every woman's partner and makes out they would rather be with her.
She drives me and M mad because our men work with her, obviously they have to be pleasant but they and a lot of the other men seem to think she's hilariously funny. She 's 30, never been married or had children. I have tried speaking to my fiance about her he just laughs and says she's one of those women who is good for a laugh and drink with but not to be taken seriously, he agrees that she should not come to the house or that he should go to her house, he does like her boyfriend ( he is nice) and will have a drink with them at M's partners house.

most of the poles won't let her in the house but if they see her at anyone else's or in the street, she's really upsetting M and M's partner is unsympathetic. Any tips on how to handle her?