Why would someone make up these lies?

[Matty]

the better question "how did she find your email address?"

As i have never been in your situation, i can only offer some more questions for you to think about. For one, maybe the reason its so unsettling is because your Husband hasn't told you everything. My father and mother tell each other everything, i can recall a very ackward conversation when my dad told mum that (an accountant) had to go visit some woman and she was practically naked, i remember mum laughing her head off. Thats usually, IMO how things should be dealt in a caring and loving relationship.

You might not like this "do you believe that there is any truth to this womans accusations?"
Your husband could also just be getting sick of you bringing up the past. "what do you want? closure, better answers?" however, that being said, for your husband to get angry over what he describes as being a small, infatuational relationship when you bring it up...to me that means somethings up. If anything he would laugh about it, crack jokes, usually thats what you do when you reflect on your past mistakes, you chock it down to experience and move on. Maybe he is with holding info like last time. Be careful, but you do have a right to know, now, especially since you have been brought into the mix, its his fault that his past is now involving you. but seriously how did she get your contact details. be careful.