Me and my girlfriend have been together for 8 years and have 3 kids. Now her mom and my pap met and want to get married which would make me and my girlfriend related. Do I have any right to stop the wedding and if so what do I do? The wedding is tomorrow. They had to hide it from the whole family, so I just found out.

Your parents' marriage doesn't affect you two in any way biologically, so no reason to stop it. Sounds like one big happy family!

Your parents' marriage doesn't affect you two in any way biologically, so no reason to stop it. Sounds like one big happy family!

We planned on getting married in less than a year and they knew that now if I let them get married according to my states laws we will not be aloud to get married because we will be cousins and my pap has already been married 5 times and her mom 3

ANY question on law needs to include your general locale as laws vary by area.

But I don't know where you get the idea that because you are cousins by marriage you will be unable to marry. If your state does have a prohibition against cousins getting married then it is restricted to blood cousins.

I am, in fact my own second cousin. My grandmother's mother married my grandmother's father-in-law (though this was after my grandmother was married). This made my grandfather and grandmother step brother and sister. Which made my mother's siblings also her cousins. As well as making herself her own cousin. Which makes me my own second cousin.

While I can understand your being upset about the secrecy, their marriage has no impact on yours.

No, you will not be cousins, if they marry, You are confusing family by marriage and family by blood, if they marry it makes you nothing, just something by marriage which is not related.
You are reading way too much into this.

This has no effect at all on your and your girlfriends relationship, if you are so worried about it, get married first, since after 8 years and already 3 kids it is way over due, a quick court house wedding and you are married before theydo.