Focusing on the positive is exactly what you should be doing. You won't always be able to manage it, so do it when you can.
If you're E-mailing your husband, I'd even try to keep your E-mails brief and upbeat, very positive.
You don't see the problems in your marriage as being all H's fault, or all your fault either, and that's a good place to start. Hope you're checking into the recommended books!
