It's nothing to do with veto power. Guy is in vee, partner A gets diagnosed with herpes, guy does right thing and tells Partner B. Partner B says she is unwilling to continue relationship with guy if he still sleeps with Partner A because she has diseases. Partner B's ignorance about stis and hysteria means she won't listen to rhyme or reason. Happens often. Guy is left having to end a relationship because of myths and ignorance.
And yes, ignorance offends me greatly.
Well I'm not ignorant about STI's, but I can sure see ending a relationship under those circumstances. Guy in this case has the option of telling partner B he wont end it with partner A, and then partner B can go ahead and choose to break up with Guy if its that important to them to not get HSV2.
MY partner B has made it clear if I get HSV2, they will stop any sexual activities with me that could expose them to it. They sure aren't ignorant, they just
don't want it, and they dont want to pass it along to their other partners, or be responsible for passing it to their metamours.
That means if somebody I date tests positive, I'm in the position of changing the sexual dynamic with, or breaking up with at least one of my partners. I dont like that, but I think it's a perfectly valid view for my partner B to have and enforce.
Now my husband (partner A) had a very low positive blood test for it a couple of years ago, the first time he ever got tested for it. He's never had a visible outbreak of any sort, and two follow up western blots from the U of W have come up with indeterminate results and no clear yes or no response. I get tested every six months on the chance that he really has it and I get it, I will know as soon as possible and can let Partner B know. Partner B has determined his risk to be very low since Partner A hasn't had an outbreak and has non-clear test results, but again, its his body and he gets to decide where that risk line is for him.
Edit: That means I will not start dating somebody new who has HSV2, because I value the sexual aspects of my relationship with partner B, and don't know that it would keep working if we took that out of the picture. I know that there are lots of awesome people that might rule out, and I if Partner B is out of the picture some day, I won't care because I consider HSV2 to be no big deal, but we all get to choose our risk levels & priorities. I made it clear to partner C early on that if he got it I might choose to break up with him, now that its an established important relationship, that's where things get complicated if anybodies STI status changes.