A child’s dad can order a DNA test.
All you need is the child’s hair, nails or blood. Job done. And it can be done secretly.
You don’t need to ask a woman before doing a DNA test. You don’t need her permission. At all.
Don’t let anybody guilt trip you.
Pass this on to all men.
Of course, notice I said “the dad”.
So you need to be legally recognised as the child’s dad. (If you are named on the birth certificate as the child, then that’s enough).
So in that situation, you have the parental right to order a DNA Test by virtue of being the recognised dad.
Also notice I said “child”.
That means the child needs to be under 18 for the dad to make all the DNA decision alone.
Once the child becomes over 18 years old, you will need to legally take consent from them too.
So in those >18years, the consent of both dad and child is taken.
So don’t let anybody guilt trip you.
You don’t need the mother’s permission to do a DNA test for your child.
Especially if you know you are dealing with someone who will twist it to mean you don’t trust them if/when you do the DNA test.
So do the test secretly- if you need to.
If you find out the child is not yours,
You can at least decide on your own what to do about that finding. You can say nothing and move on. Or take it up with your wife.
If you find out the child is yours too,
You can easily decide to keep your mouth shut to avoid undue tension.