I think I am going to ask my wife to keep from teaching our child to say please and thank you.
Do you think this may be an issue later on in their life?
Yes, it annoys her so much when she tries to keep them that she starts cursing and that's annoying.
Both parents are expected to parent the child. It is expected that you both teach the child, especially when it comes to manners.
You are taking things too seriously. I don't want to teach my kids how to say please and thank you. They're not in elementary school anymore.
While you may feel your child is too old to be reminded to say please and thank you, that may not necessarily be the case. If you child still forgets to say please and thank you then you should remind them. Once they do it on their own consistently, this is when you should start to taper it down.