M45, looking for advice about wife.

So, the last few times we have made love, she hasn't been able to have an orgasm. Prior to this, it was usually pretty easy for me to get her there. I would go down on her and use my fingers inside. She would have very nice orgasms. But lately, she gets so close, but it slips away. I know what feels incredible to her, but her body just keeps saying no. And she always says it did feel amazing, but she doesn't have that finale. Any advice would be very helpful.