Perhaps if in your discussion with your husband, you would stress the higher goal.
If your husband gets [Mod edit: upset] about the Church’s rules and regulations about sex, ask him why he thinks the Church has all these rules.
Is it because the Church seeks to protect us from being corrupted by sex?
Or is it because the Church seeks to protect sex from being corrupted by us?
You and your husband may be astonished to learn that it is the latter that the Church is seeking when she teaches us about the morality of sex.
Perhaps if you and your husband can begin to understand why the Church teaches what she teaches, the motivation to practice it will grow.
Finally, if you know some good faithful families in your area it would be a good idea to make a network of friends that are good for you. Invite couples over for dinner and let your husband hang out with the other guy for a while. Do this regularly. If your husband hangs out with guys at the bar who talk about OS and how great it is, he’ll want that too. If your husband hangs out with other Catholic men who practice NFP, and they talk about how great NFP is, your husband will begin to desire that. Be careful that you pick men that are your husband’s “type” though. I for one struggle with prejudism against frail and less-than-hearty men. If my impression of men who practiced NFP was all girly-men then I’d really run away. However, if I was exposed to guys who lift weights, shoot guns, and practice NFP I get a totally different impression.