I think after fifteen years together, you and your husband owe it to yourselves and to your children to figure this out. Sit down and have an open, honest conversation. Without yelling or blaming, calmly explain your own feelings. Tell him your fears and concerns. Ask him what he wants. Tell him how hurt and isolated you feel when he refuses to speak to you. Ask him if the two of you can come up with some better, healthier ways to communicate. Suggest that the two of you get into counseling. If he refuses, I'd suggest you get some counseling.