Hello guest! Are you an Apistogramma enthusiast? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's a great place for Apisto enthusiasts to meet online. Once you join you'll be able to post messages, upload pictures of your fish and tanks and have a great time with other Apisto enthusiasts. Sign up today!
It could be that he's ready to spawn and she isn't, so he could literally be bullying her.
Do you have a hospital tank in which you could keep a seperate eye on her, away from the male? Give her a few days to perk up, with some nice fresh water, and hopefully she'll start eating again.
When she's then looking good and strong you could then try reintroducing her to the male.
This is just a guess though, there may be another underlying cause.