Kim - I can so feel your pain, and I'm sorry that you are going through this. DH Tom, 55, was dx 9/08. I had nearly left him because his anger and verbal abusiveness had gotten so unbearable, esp on the kids, who were 10 & 11 at the time. I have never feared physical violence, but the downright nastiness was awful. I know every situation is different, esp with brain tumors, but I can tell you that Tom has become more passive, not more aggressive, as this disease takes its toll. The kids are aware of what's happening and we have never avoided using the word "cancer".
Do your kids get to spend time away, either with grandparents, uncles & aunts, or even sleepovers with friends? I'm not saying to pretend the elephant in the room isn't there, but my kids, anyway, have greatly benefitted from efforts to get them out of the day-to-day slog of criticisms, unkind comments (remember: with no impluse control, if Tom thinks it, he says it out loud), etc.
If you don't have a support group yet, can your n/o or social worker help you find one? You have needs, too, and making sure they are minimally fulfilled will free up so much more of yourself for your husband. I just mentioned in another post a free online site that our doctors told us about -- http://caringbridge.org. You can set up an online journal to tell people what's going on, and they're able to sign a guest book, I find the writing cathartic, and reading the guest book to be energizing. It reminds us both of how very loved we are. I highly recommend it if you haven't already started one. You can have it open to anyone, or you can limit it to friends and family; you can update it as often as you like. I don't think there are any size limits, but I am no expert on the site. Just a user.