Was married 30 plus years. Due to circumstances the attendance at my daughters wedding will be 90% my exes family. Why should I pay for my exes family? I know its my daughter's family but .......

the only two important questions you must answer are:  

My son got married a few years after our divorce, and while the bride's family did carry the bulk of the cost, there were some expenses like booze for the wedding and the wedding party dinner the night before that the groom's family typically covers.  There was also the wedding gift to the couple to consider. So i asked my ex to pony up half of that and she agreed, somewhat hesitantly, but she knows this is a 50/50 deal still so she agreed.

But in any case it's your daughters wedding. It's a happy joyous occasion. Pull out your wallet and have fun!!! Congrats!!!

Honestly, your daughters day, don't screw it up!  Some things are priceless

Set aside you and your exes differences for one priceless day. Your daughters happiness should not come with a price tag.

Because you love your daughter and she loves them

No chance of splitting the costs with your ex as its all her family attending the wedding?

First for making it 30 years in a marriage, and on your daughter getting married. Seems to me a father of a bride being obligated to pay for a wedding is so antiquated.

You get a proper dowry. i'm thinking 10 goats, some chickens and at least one cow.

This is your daughter's event.  Give your daughter a check to subsidize the wedding expenses for however much you think is appropriate as opposed to getting involved in the details of the wedding.   Then dig deep and double or triple that.    Worst case - you might have to cut down on the hobby for a year or two....

is what you should celebrate. Time to set the ex-enmity aside and take care of it because you love your daughter and her happiness and special day come first

This is your Daughters day, plain and simple.