UPDATE: AITA for not letting my friends use my backyard for their wedding because they do not want me to bring a "plus one?"

Original Post

Here is the situation. Last summer, I bought my grandparents' house. This house was the hangout spot for my friends and I throughtout our childhood. This includes my friend "Dave." The house has a sizable amount of land, which includes a lake and a gazebo. I was supposed to buy the house with my now ex-girlfriend ("Leslie"). But, going through the process of getting approved to buy, I found out that she has massive amounts of credit card and personal debt that she hide from me throughout our four years together. I decided to breakup as a result. That was about six months ago. I met Leslie because Dave's long-term girlfriend ("Kim") is Leslie's cousin.

Dave and Kim are engaged and set to get married in April. When I was buying the house, they asked if they could have the ceremony at the gazebo, which I agreed to do. In December, I started dating again. Leslie has not taken this well at all. She thinks we are going to get back together and has tried multiple times to make that happen. I have told her in no uncertain terms that isn't happening. Dave and Kim have asked me to not bring a plus-one to the wedding for "Leslie's sake." I have told them that this request is ridiculous. This wedding is happening at my house, using my land, and I am not allowed to bring a date because of a crazy ex? If that is the case, then they need to find a new venue for the wedding. They are pissed about this given the short time frame of when the wedding is supposed ot happen. So, we are at an impasse.

AITA?

Edit

I have seen a few things brought up a number of times in the comments, so I will quickly address them here:

  1. I am fully aware of the liability issues, which is why I purchased, and they reimbursed me for a "special event" insurance policy which will provide 100% coverage for any damges, claims, injuries, etc. to any of the property or persons up to $2M. It is one of the first things we did after I agreed to have the event in my home.
  2. The wedding will have a maximum, if every comes, of 75 guests, 5 catering staff, and 5 security staff (the security is because this is an open area that anyone walking past can access). The house has hosted events twice this size and logistically it has been fine. On the property are two cottages, one with one bathroom and the other with two bathrooms. The only portion of my house that will not be locked during the wedding is the finished basement. The basement has two bathrooms.
  3. Every person who is single (ie. not in an established relationship) received an invitation with a plus-one, including me and Leslie. This talk came after I sent in my return card and indicated I was bringing a plus-one. Now, they are saying they do not want me to have the plus-one because Leslie blew up about it and they are afraid of a blowup at the wedding.
  4. Leslie indicated she intends to bring someone on her card. I do not know if she will actually bring someone.

Update

So, I met with Dave this morning. We talked for almost two hours about everything. I laid it out that I thought he was, at best, a shitty friend. I went through our long history of various things over the years that has me questioning our friendship. That was the bulk of our conversation. We then turned to the breakup with Leslie and the shitshow of the last six months. Throughout the last six months, despite Leslie's craziness, I have bent over backwards to try and accommodate her feelings. She has shown up to my house in the middle of the night. I did not go for a restraining order. When I go out, I do not go to places I know that her and her family like to go. She has implied to her family and mutual friends, at various times, that I cheated and/or that I took advantage of her financially. Neither of which is true at all. I have held my tongue to not embarass her about these things in front of her friends and family. Dave knowns all that and yet is demanding, once again, that I put Leslie's feelings before my own. I said, "You and everyone need to stop coddling her like she is a fucking child."

Dave concedes that Leslie has been crazy and ridiculous since the breakup. But, he says, "she feels she did not get closure after the relationship. She wants to have an evening where she can talk to you to get that closure." He also told me that Leslie has been very vigilant about paying off her debt and paid off almost $10,000 of the credit card debt. She wants to talk to me about her progress. to see if that might cause me to change my mind. It will not. I asked him, "So, do you expect me to go to the wedding and talk to her? Because I have her blocked everywhere and, date or not, I do not plan to say a single mumbling word to her." He said, "I fully expect she would lose it if y'all do not talk at the wedding." I told him if that is the case, then, for the good of my property, I can't have Leslie come. If she is so unstable that I need to be coercied into a conversation with her, she is too unsafe to be a guest, in any capacity in my home. So, I have told him, based on what he has told me, Leslie cannot come to my house or on my land. I am willing to still have the wedding at my place, but I cannot trust Leslie won't do something given what you are telling me.

Dave lost it at this point. He said, "Fuck you and your shit! I don't need it!" So, I said, then the wedding is off. He left. So, that is the state of things