How do you know when it's time?

 IME, you just know. The last dog I had to euthanize didn't want to get out of bed, that morning, I called her out, and put her breakfast down. She was a chowhound, but she sigggghhhed deeply and ate very reluctantly. She'd been telling me for a while that she was tired. That day, she looked up at me, and said, "I'm finished. I've had enough. Help me," I called the vet, called a friend to drive us, and we went. Her kidneys were failing, and I didn't know, until she started puffing up on the way to the vet's. She was ready. She told me she was ready, and I've not doubted it for a second.

agave

This one really needs to be my husband's decision but I don't know what he's thinking and know he doesn't want to talk about it.  I really don't want him to feel like I'm pushing him in a direction he doesn't want to go.

i went thru something similar when our lab had nasal cancer. He had been my husband's dog before I met him and it took him longer than me to accept what was happening. We were given the same dismal prognosis that it wouldn't be long but it could be a painful ending and I worried about that constantly. I tried to discuss it with my husband but he kept saying "but he's still wagging his tail and eating good". That was true up to the last day Jake was with us, but he was clearly in pain. It wasn't until one evening that we gave Jake a piece of ice and when he tried to eat it, he screamed in pain. That was enough proof for my husband and we said good-bye the next day. When we walked in, our vet took one look at Jake and said "oh my, it's definitely time".

Rather than being the one to talk your husband into this, I'd try to get your vet involved. Your husband will probably listen to him and there won't be any resentment later about having done something too soon. I'm sorry you're all going thru this. It's the most difficult thing we have to face as dog lovers but it's also the most compassionate and selfless thing we will do.

 Well he doesn't seem to be in denial, he started digging a hole today.   Tomorrow I'm taking a cat in for shots, I'm also taking a picture to show the vet and get more pain meds.

Like others have said, usually there is a point the dog is in too much pain and the dog lets you know s/he is ready. Maybe they stop eating, don't want to walk, cry, or maybe you just see it in their eyes.

Yes. get the vet involved. I don't know if there is a way to drain the tumor now or to treat a tunor once it bursts. Bonita would know. She has fought some cancers pretty successfully. My dogs have had cancer but didn't survive long after diagnosis.

When to let go is the hardest decision you will probably have to make for your dog. My thoughts are with you, especially since I remember how complicated an infant can make your life.  Hope you keep us posted.

Agnes

 Well tomorrow is the day.  The tumor is so big it's causing problems in his mobility and constantly oozing.  He spends most of his time licking it.  All of his food seems to be going into growing the tumor, and he's getting thin.  The vet is comming out in the morning so he doesn't even have to be bothered with a trip to the vet.  I wasn't sure it was time when I made the apointment on Tuesday but every day I'm more convinced it's the right time. 

I'm really sorry that the time has arrived. Even when you're sure it's the right thing, it still hurts like heck. My thoughts will be with you tomorrow.