@Firelover,
I bet she's sleeping with him, too, and may very well be pregnant by him. After all, she can't exactly suddenly have a kid in, what, 6 months and then say, "
Oops, honey, I guess it was a virgin birth 'cause we haven't been having sex! Oh, and by the way, don't leave me because I get great sex on the side but I enjoy the lifestyle you're providing. So go out and keep making money, little man, chop chop! 'Cause sexy baby needs a new pair of shoes!"
I'm sorry that's harsh, but if we assume she is being 100% truthful to you (and we cannot assume that, seeing as she is lying through her teeth to her husband every single day - so her reputation for veracity is in question), then she will be kicked out of the marital home when she has the kid, and probably before, as I doubt her husband will be so clueless as to not notice that she's pregnant and they haven't been having sex.
Seriously, consider this logically.
- She doesn't have sex with him but she's pregnant. He is going to notice.
- Or she has sex with him in order to cover up her pregnancy. That makes her a liar to you and a manipulator to him.
- Or she was sleeping with both of you at the same time, meaning she's lying to you.
If - big if - #1 turns out to be the case, then she'll be tossed out on her ear pretty soon. And she will come knocking on your door, to live with you and have you claim paternity on her kid. And good luck on keeping her faithful, seeing the track record that she's got.
Oh, and do get a DNA test.