I understand she must be upset but also kind of think it's not her place to have a say on what he does about me?
Not her place?
That's a very confrontational phrase to use. Surely you can see that while yes technically she cannot and should not control what he does here, the fact is that he's put a bomb right into their marriage and family. It affects her in every single possible way - her own children have a half sibling she never knew existed, her husband has misled her, she is looking at potentially having an adult stranger suddenly placed into her nuclear family. Many people would not choose to have a family with someone who already has children, for all sorts of reasons - that choice has been taken away from her. She must be absolutely devastated right now, regardless of how she may come to feel in the future about you as a person.
I have to say, while you are entirely innocent in this, you using phrases such as 'not her place' when you talk about the personal relationship between two long married people you didn't know from Adam this time last year - if you are thinking you might want to be a part of your biological father's family in some way, that's probably not the best way of thinking to start off with. She has every right to be at the centre of this and every right to feel the way she does about her husband and father of her children not telling her about this. Don't take this personally to the extent that you deny that- you must know her reaction is pretty understandable.
I know I sound harsh, and I will tell you why. I think you need to tread carefully. He didn't tell his wife about this. Now he's happily telling you about how she feels - as SleepWarrior says above, my gut reaction is that he doesn't sound great. I have a horrid feeling that the kind of man who seems a bit oblivious to how big a thing this actually is for his own wife is also the type to be super enthusiastic with you until the novelty wears off, and then you won't really hear from him.
Tread VERY carefully. Try and think about the long term implications of however you handle this. Be just a little bit suspicious of a man who so readily talks about how his wife feels about such a big thing, so casually, with someone who's still a stranger.
Don't assume that how people feel right now won't be changing very rapidly - in both directions.
Don't villify his wife. She's actually the one reacting more normally, if anything. Don't assume that she's 'against' you as a person - right now she must be in shock at her husband not having told her about this - it's not really about you, it's about her and her own family.