Jumping into a can of worms here...
Women are emotional. It's true. Husbands may not like this and our priests may not understand this, but you can't just say to us "You owe me my debt." This is a sure way to grow bitterness in a woman's heart. No matter how true it is that as spouses we owe each other our marriage debt, this doesn't really mean much at midnight when she has to get up at 5 to start her days work.
As married women, many of us stay at home mothers and often separated from our own mothers, we sometimes find ourselves in emotional isolation. We don't want to be gossips or cause people to look at our husbands unfavorably, but we do need our female friends. In case you are a man, you should understand something about women---we don't want you to solve our problems--we want you to LISTEN to us. We don't want lectures and theological condemnation. We want you to hear us...our concerns, our anxieties, our frustrations. For Pete's sake, we know about our marriage debt, we really do, but we want you, our husbands, to hear us.
As a former practicer of NFP, I would also caution you on something that happens to many women emotionally. And here again, I mention feelings. Women are emotional people, we have feelings. You should be glad that we do and work with us because it's our emotions and feelings that actually keep our homes warm and our children loved. When we practiced NFP, I felt like a prostitute. I felt like my husband only wanted to be with me on certain days depending on how secure or insecure he was at the time. It was very hurtful and it put a large wedge in our relationship.
Relationships are very complex. Marriages are very hard. We aren't perfect and sometimes we expect more from each other than we can give. Some women and some men are very needy. Some men and some women are very detached. Pairing these together can make for a lot of hard work in the intimacy department.
To the OP, I encourage you to really sit down with your wife and LISTEN to her. It may seem stupid to you, but this is how God made us.
I don't know what your wife is experiencing. But if you really want to solve this problem and have a meaningful relationship with your wife, then you will move beyond this idea of lecturing her on her obligations to you, and really start listening to her.