So, we get engaged, everyone is very excited, congrats all around!!! yeah!

The day after we are calling everyone to tell them, and here is the response from my fiance's dad, "are you sure you really want to do this?" Seriously? Lets start with if you knew your son at all you would know that he doesn't make decisions lightly.
So, things progress to about 2 months later, and he's hanging out with his dad for the day. It started with 1. what a horrible person they think I am 2. didn't like where we are getting married 3. when we are getting married 4. asked how my parents were going to help us, because "they don't seem that well off" It was just a slew of nastiness. First off, insult my momma and I will freaking stomp you to the ground. Secondly, they (dad and step mom), because they no longer have control over his life. When I came into his life a few years ago I was shocked at how crappy his dad treated him, yet how he "controlled" his adult son. So, we changed some things.
They don't want to be apart of the wedding is what they say. So is it wrong to not send them an invitation or include them on invitations and announcements? Frankly at this point I'd rather cut off a toe than deal with them. The rest of my fiance's family has been wonderful and are all looking forward to everything. I just don't know how to deal with this properly.
Before someone suggests "talking to them", we have. It ends in yelling/and or crying.
Weddings are suppose to be happy times...and as long as the words "dad and step mom" don't come up in our household, we are happy!