I don't know if she is being perfectly honest with you. She says she wants you, but won't have sex. Tada. She's lying. Or if she wants you but WON'T have sex, she has issues and it's probably not worth it.
How long has her h been working 3 hours away? That sounds terrible. Did she decided to dally with you BECAUSE he was gone all week and she was bored, or horny? Now, she's saving her horniness up for the weekends and the baby-making, and letting you lie in the next room LISTENING? Not right, not right at all.
I think you served a purpose during her NRE, it was fun and exciting for a while, but now her actions are telling you, she's done. She's got other things to worry about. Like FOL said, in her situation. It seems cruel in some ways, but sometimes relationships do not last past the NRE stage, and her NRE was shorter than usual because of the stress of her h being gone and because all of a sudden she's got baby fever.
I'm very sad for you.
PS, if you don't break it off, I'd also recommend when her h comes home, you don't be there. Go to your place, see other friends, do your hobbies and work out, treat yourself to a spa day, whatever! Give them space, and don't be there listening to their sex sounds!