I think it's probably going to tell you more what you DON'T get.. many times it will mean that you are entitled to less than the law would otherwise allocate in a divorce.  But he has come in with the majority of the wealth.

Obv yes.. there should be an attorney on your side reviewing and advising.. and yes.. it is somewhat of a negotiation of terms and wording.. 

Sometimes you may be entitled to more the longer the relationship.. or rights to live in the marital home for some time or even lifetime rights for longer term relationships.  There may also be stipulations that you get nothing if you walk away or if you cheat or cause the breakup.

I'm guessing that your Skids are in part against you because they see it as potential loss of some share of marital assets and inheritance. 

are you sure this is the route you want with this guy?

Second marriage. Me widowed. Him divorced then ex died. Both of us had 2 young adult children. Ours basically states that premarital assets are separate unless we retitle them together (not happening). Whatever we do after marriage is joint.

We each had our own lawyer. He visited his lawyer first (no reason, he just got the first appointment). His lawyer sent mine a draft proposal. Mine revised and sent it back. Repeat a couple of times. Both lawyers agree it's fair. We sign.

I asked for the prenup.  My reasoning was that my assets included what I inherited from my first husband, and that should (if anything left) go to my kids, not his. His kids received what their mom had when she died. He agreed. 

You definitely want your own lawyer. There are some things in our prenup that I had never considered and added. 

A few $100 for a hour of a good lawer time , going over all of this.   I assume your SO has assets he wants to protect.  Or wants his kids to get the property gathered by the ex for there kids.   Since they got the ball rolling.   What ever they want to protect must be separated some how.    Because any wealth gathered in your present marrage is split 50/50. Or. 70/30. Because other money is protected.   
'What is they trying to protect. Money, property. Stocks, ?     Because let's say they had a house with the ex. It's now get valued by a proper  person. It's worth $100.   Does the $100 get protected or thirty years down the road the house is worth $500.  Does ? ?  The kids get $500. Or kids get $100 and the remaining $400 is community property of marrage ? 

Prenups are not unusual for a second marriage. I was the one who wanted the prenup. I had inheritance from my parents that I wanted to protect. I brought assets and he brought debt. We used the same attorney, but she advised that one of us use a different one. But DH and I agreed on everything with no argument. 

Now, 12 years later, we amended the prenup to handle the marital home differently than we did originally. We did that in tandem with updating our wills. 

Yes, engage your own expert lawyer to review.  Generally ownership of property and assets  prior to the marriage remain the property of the pre marriage owner.  Anything acquired after is co-owned.  

Unless there is significant wealth on one side or the other prior to the marriage some laws minimize the need for a pre-nup..

Verious stipulations regarding adultery, etc.... can be part of it as well.

The concept is not one I have a particular issue with though IMHO it is kind of a self fulfilling prophesy at some level. At least when one or the other partner is of nepharious character.

I'm going to say this as gently as I can, you need to be very, very careful about agreeing to things in this prenup. It sounds like your SO has lots of money and probably knows a whole more than you about financial things. His children do not like you, and he has not been very supportive of you when it comes to his kids. I guarantee you that they are in his ear about his estate. You do not want to be in a position where if he dies you don't have a home. Please get a very strong attorney of your own, who has absolutely no connection to your SO, to negotiate for you in regards to the prenup.

You usually sit down and discuss what you want ot keep if the marriage doesn't work. Then you have it written up. You can type it up yourself or have an attorney do it for you. Then you have it notarized. You can use legal documents available online or hire an attorney. You should hire your own attorney if you can't agree, want advice or are having trouble with the legal documentation aspect of it. DO NOT get married without one. I would be very wary of anyone who is against having one.

Pre nup are one thing. But if DH dies he still has responsibility to you and your kids, to provide for you and your kids to finish college ect.  Not you are living in your car, and someone else is getting millions