Your partner is being unreasonable.  Why should he expect you to invite his EX WIFE?  It doesn't matter that she is the mother of his children - she is ex wife and is not entitled to invitations to an ex-spouse's events.  And the fact that he wants to invite her knowing she is rude to you?  No way.

If he's insistent that he absolutely wants her there then, at very least, the celebration should be removed from your home and transferred to a restaurant. You should not have to feel threatened in your own home. 

However, like Caninelover, I wouldn't invite her in the first place and for all the same reasons.

You feel like crap because he is treating you like crap. He's being selfish and prioritizing his desire to have his ex-wife at this party over your feelings. Ex-wife or not he should not be inviting anybody who has treated you poorly in the past.

Aside from celebrations for my stepdaughter I can't think of any reason why BM would be at a party that my DH was hosting. I don't think she would even be welcome at a funeral.

Is this a retirement party or something like that? It would be less concerning if he said that he wanted her there as his business partner and not because she's the mother of his kids. And the kids are older it's not like she needs to be there to take care of them they are adults are on the verge of adulthood they don't need mommy holding their hand.

I would tell your husband that if she's coming to your home for this party then you want to opt out of the party preparations and you're going to find something to do outside of the house that day. 

Verbal abuse NEVER has to be tolerated. You NEVER have to be in the vicinity of someone who has been both unkind and abusive to you.

I think instead of letting your partner make you feel like you need to do things for "the greater good" that you put your foot down:

"SO, I can't stop you from inviting BM. However, given how she has treated me (and list examples here), I'm not interested in being around her. If she is invited, then I will not participate in this event. I refuse to be in the same space as someone who has been cruel to me when I don't have to be, and I'm disappointed that you'd ask that of me."

If he gets angry at what is a very reasonable request, then I would reconsider this relationship. I highly doubt someone who has been cruel to you has been respectful to him and really been "great" to co-parent with. If she really has been, though, then recognize that your SO has been willing to throw you under the bus for his own comfort. That's not okay.

Well... the good thing is that historically she rejects invitations.. is there anything about this one that you think would make her change her mind?

I mean.. I'm guessing going to her Ex'es 50th birthday celebration.. or whatever is not high on her list of things to do to go and hang out with his new wife?

I think that you are well within your rights to ask him point blank.. why he wants her there.. and why he thinks she would want to be there.  The fact that they share children and a business should have nothing to do with this celebration.. unless the celebration involves one of those two shared issues.

Parting with the ex ended. There is no reason for his ex to be at his Birthday party.  Matter in fact I would insist on her Not being there.  No reason for the ex ever to set foot in your home.

 You have a problem,  your DH is still too involved with his ex.  You must stop this craziness now.  

my rule of thumb: if it's an important event or party for SS, she's asked and I tolerate his ex. She doesn't speak to me anyway so it's mutual. But if it's not something for the SS, she doesn't get an invite at all.

The ex has been verbally aggressive and emotionally abusive to you?  Why would your partner even consider asking such a person to an event you are co-hosting?  You are being reasonable.  She should NOT be invited.

Shame on him for not protecting you from her. That's is EX not current spouse. Unless he wakes up to reality that he made a choice to marry YOU , he can go back to his harpy ex.  I would not for one minute tolerate his confusion.  You can take the high road and co parent peaceably but that's where it should end.  If he insists on her being a part of his birthday, I think I might give him papers for his present.   

Since it's for him and not skids, I don't see why she would have to be invited. Given her past behavior, I don't even think she'd need to be invited for something that was skid-related. You are not being unreasonable. 

Any sane man who knows his ex wife is abusive, disrespectful and trashtalks his partner or wife frankly won't want to be anywhere near her and the whole "but she's the mother of my kids?" crap needs to stop. 

He says he wants her there because she is the mother of his children... this event is not anything to do with the children.

The mother of his children does not need to celebrate with you and your partner for his life event. It is ridiculous for him to even ask you to tolerate this woman (who has abused you) for a party that you are hosting and that has nothing to do with her.

I can't imagine my husband wanting his ex-wife at ANY of his celebrations.

Just nope. If D?H insists on controlling the guest list, it's his party--not yours-- and your role is to put your feet up, buff your nails and eat chocolate bonbons while he does the work. If it's his party, he should be paying for it, too.

As a last resort, and if she shows up over your dead body, grab your go bag leave him to the entertaining and cleanup.

Ideally you can agree on who gets to attend your parties, but if your DH habitually and continually ignores your wushes in matters like this, guest lists are the least of your problems.

That is it for my advice on this topic.

Take care of you.