My mother in law died 4 years ago , she was buried in a double plot , as my father in law would join her when he died .After her death he remarried , but sadly he died last year. He was buried with my mother in law , there was a headstone already up ,we just added my father in law details on the bottom , since then his second wife has added a further headstone which is flat , but the same size as the first head stone , we are not happy about this , but she holds the deeds is there anything we can do as it is my husband's parents grave .

The added headstone shows the new wife's/widow's name, like she plans to be buried there too? If not, what is your objection to the additional flat headstone?

Have you talked with the cemetery office? Do they have rules about additional headstones?

How do you know that it was your father-in-law's wishes that his 2nd wife be also buried beside him? Perhaps they had a pre-arrangement, and wanted everything done, hoping that it would be the right thing to do, and no one would be offended? Could they have had good reason not to involve the rest of the family in such a decision?

Have you asked his current wife why she did that? It would be better to simply ask her, rather than talk about her behind her back and assume that she's committed a terrible faux pas against the family.

I would hope you would have enough dignity, grace, understanding, and manners not to make an issue out of this.

It is his wife also. How long were they married? I think it odd, he was buried by his first wife? Who was in change of that. Often he would be buried with his new wife. I think it is reasonable and nice for his new wife to want to put something on his grave to mention her. And to show her love and caring. I will assume you did not allow her to do that on current stone.

I think it is bad that you have such poor feelings for the new wife and women he loved. To treat her so poorly in her husbands death. This was HER husband, you are treating her like she is no body

Honestly - a little strange, but he loved both of them. I'd leave it alone. I'm sure the first wife is in a better place than to be bothered over her husband remarrying after her death. Marriage is until death. She died . He kept living. That is how it a meant to be.