I am a big advocate for, if you want/need something, you are responsible for asking for it. You can't hold someone else accountable for action or non-action if you haven't told them you need it.
So your first step is to sit down with your wife and partner and tell them that you need this from them. Have an honest discussion about what's happening with you and your hearing and tell them is reached a point that communication has become to difficult without the sign language. Make sure you get promises to learn from both of them.
Then keep on them about it. Give them information. Advise them of classes and resources. Set aside time to practice.
If they refuse, or don't follow through on their promises, then it might be time to look for new people to form better relationships with.
