Your husbands moral high ground is to tolerate a Jeremy Kyle episode involving his family and child?
How unattractive.
Absolutely no way would this be going ahead with these dregs of society type.
For business owners I would have thought he would be well versed in public liability insurance and how vulnerable you both would be if anything were to happen on your property.
A fall, twisted ankle, anything could happen.
Check this out with your insurance company, asking for exactly what your existing policy covers you for hosting a wedding etc.
You also would be liable for the catering staff.
Unless I'm missing something and you have a big expensive existing policy for these types of events, you are both being spectacularly naive.
Check this out thoroughly and I imagine what you will be told will be the perfect exit from this.
I wouldn't trust a liar like her not to encourage someone to make an opportunistic claim against you both.
Do not do this.