First of all, I'm wondering if you had a talk with your daughter about sex... if you haven't, then you should. Don't wait. She needs to know that you are the mom. Tell her how much you love her and that she was made with love, and that you and your ex wanted her, etc. Therefore, sex should be something she should be careful with. And that if at any point she feels she is ready for sex, then that you would help her get pills, or any advice she had.
The reason I say talk to her about sex, if because she needs to hear it from you. Not your hubby... sorry. I just don't trust men much. As a mother, I think you need to keep that guard up all the time with your children. If she feels that misses dad and is upset that he is not in her family picture, then think about what she is doing. She may want you to be upset with him for being too close, or she want to see if he tells you and then he not trustworthy to her. Either way, I think she need you to talk to her. I don't see anything wrong with her telling him things, but since you said she is upset that her biological father istn' around, then this might have a meaning more than what it looks like. She knows that's not her father, right? She knows she can tell him anything and if he gets her in trouble, then she has more of a reason to not want him around.. anyway, that's just my especulation of this.. I may be wrong.
But I just think it is kind of weird. And also, have they been always close? Or has it just been lately? Anyway, you must never take anyone else word but your children's. So, you do need to talk to her. Don't tell her that he told you. Just go out, do fun things.. and then tell her about that you understand that she misses her father, but that it's ok.. she's got you. Tell her she can count on you for anything and that you will always be on her side... "make sure you say that". You should also talk to her about your first time, etc.. tell her how scared you were and that back then there weren't so many precaustions like now.. etc.. and that there are many things to worry about, not just getting pregnant. So, I think if you open up a conversation where you are telling her your story, then she might just tell you then. Don't say you know... just let her tell you. Don't be upset, she may have done that on purpose. It's humanly possible that she wants to get you back for her not having the life she wants.. "as she sees it". It's not your fault, but do ask your husband to suggest to her to talk to you... and then that might help too. If he's a good man, then he should know better than to keep bounderies as to what he can talk to her about, and what not to... otherwise, you are have the wrong kind of connection there! Honestly I wouldn't feel confortable with that. But then again, it all depends on their relationship while growing up.. were they always close, did he do fatherly things... did he teach her how to tie her shoes, that kidn of bond... if he wasn't there, and all of sudden he is taking interest in her sexual life, it is no good.
I hope you don't get offended, but it's always good to hear it from different points of view.. and that's just one. I do not know your story, but I know you are saying this is not her dad. And even if this was her dad. It is not usual for a girl to tell this to a guy! Unless... he is giving her the impression that she can talk about these sort of things with her...is he talking about things like this too?? Not good. You should be doing that. It's a mom thing. No matter what people say, I still think that you need to get in the middle and back him off, no matter how nice he is. That's your girl.
Let him know that.. I'm sure if her's a good man, he knows., and that's why he told you... but just in case.. men are hard to figure out too.. anyway, I've seen a lot of these cases.
And let her know that she's your baby.. always.
I feel for you. I wish you the best.
By the way, don't let him take her to the doctor.. no no.. You should.