Sigh.
It is. You need to talk to your SO in advance, so both parties know what the expectations are. You may need to have qualified legal counsel draft a pre-nup or equivalent to address local legal requirements. None of that requires state mandated testing, much as the fact that some men cheat does not justify you being forced to undergo regular, state-mandated STD testing. Still, some men do cheat, so I assume that you are down with your spouse asking that you use
one of these (may be NSFW in some regions). Right? Sauce, this is goose, that is gander.
As a side issue, since all women are cheating <censored, etc.> you have, of course, had your own paternity tested, right? After all, everyone here saying women are cheating <censored> have just said that about their mothers -- you bastards. Of course, you are also able to verify that your father really did have to work late that night, and never dipped his wick with that secretary. /facepalm
Short answer? If you want a paternity test, it is well within your rights to request one. If local law does not support that, work it out in advance with your SO -- "Baby, I love you and want to be with you, but you women can't keep your legs together so I want a paternity test if you get knocked up." If you can't sell that, the LGBTQ community doesn't seem to have the same problem.
Cheers!