To follow up... apologies for the wall of text. You can probably tell I've been thinking about this a lot.
I've been observing him closely over the last few weeks. If anything, it's worse than what I described in my original post, because it's not simply a matter of him behaving this way at the door when he's about to be let out. He is now constantly on alert about the possibility of going outside. He's started to associate it with me simply moving a chair or walking near the back door. I have to make sure I know where he is and potentially call him over before I stand up from a chair because he will excitedly charge down the female from across the house and leap on her and get in her face growling. If I stand between him and the female, I can see he's visibly very anxious, chattering and licking his lips. It doesn't matter if he's fast asleep or he's just been out for an hour-long run. His home life centres around this very specific obsession.
very specific. I said earlier he is "somewhat dominant" of the female at home. Some mild examples would be getting in her face around meal times, and trying to stop people from giving her attention when they greet her at the door. None of this has ever been a major issue, and I've been methodically working around it by making him sit and stay until he calms down, or distracting with a toy or game. Most of the time this isn't even needed anymore. Meals and visitors are no problem now. I can give her a treat with him standing right in front her without any issues. He's never displayed any resource guarding with food or toys.
This all changes the instant he thinks he'll be going outside with her. I've been writing this post all day, and it's really difficult to describe. He is obsessed with the actual act of getting in and out the back door, secondary to licking her urine.
Originally Posted by Bob_McBob
If I let him out first, he will either turn around and jump on her or else charge her down from across the garden. If I put her out without him, I have to physically restrain him while she goes in and out. It sounds like I'm murdering him: wailing, barking, crying, foaming at the mouth, and so on. He is 85 pounds, and I wouldn't be able to hold him if I weren't a big guy. Once the two of them are actually outside, he's perfectly fine.
I've tried taking him outside and playing for a while before she goes out. If he catches a glimpse of the female near the door inside, he loses all interest in the toy and wants to stand near the door waiting to attack her when she comes out. This dog was born for SAR and will spend hours on end fetching balls, 20+ minutes looking for a single ball in the snow, etc. The fact that this obsession tops that drive gives me great pause.
If I have him lie down and stay and hold him, then have someone let the female out, he loses his mind just the same way he does inside, barking and crying trying to get to her to the point I can barely restrain him. 10 seconds later after she's urinated, he has zero interest in her and wants to get to the urine. Once he's had a good lick of that and marked on it, everything is perfectly fine and I could leave the two of them outside indefinitely if I wanted. I can avoid the bloody murder screaming by very slowly introducing her to him at the door as I let her out and correcting him several times when he tries to lunge at her, then making him stay while she pees. I suspect the whole idea of restraining him from attacking her while I let her out is very bad training.
I made an interesting observation a couple days ago: when I physically stopped him from getting to the urine, he frustratedly redirected back to the female and tried to do his dominance leaping/growling routine again. I'm not sure what conclusion to draw from that. It's also worth noting he doesn't display any of this behaviour at the front door when either he or the female enter or exit. It's entirely limited to passing through the back door in anticipation of the female urinating.
After initially posting this thread, I made some attempts at crating him while the female went outside. He hasn't been crated since he was a puppy, and it wasn't terribly "successful" except that it physically restrained him from her. I should have pursued this avenue rather than trying to calm and restrain him as described above.
I am now reintroducing him to the crate in a more serious way. He is crated every time the female goes out in the garden. When he needs to go outside, I take him out the front door and pass through the side gate. With this method I can actually crate him, let out the female, take him through the side gate, then let the two of them socialize in the garden without even the slightest hint of an issue. When it's time to come in, he goes through the side gate and back into the house, back in the crate, and then I let the female in. It breaks the middle step of passing through the door that most of this behaviour relates to. The back door is completely off limits to him for the time being.
This method is far less stressful than restraining him myself. Sometimes he realizes the female is going out while he is in the crate and does his usual crazy behaviour. Sometimes he doesn't. There isn't a location in the house where he can't hear the door being opened. If I let her out and back in without letting him out, he always realizes she has been out and will follow her around trying to sniff her back end and lick the floor where she's been sitting. So far it hasn't lessened his obsession with the back door, but it's my hope this will diminish as he realizes he will not be going through it anymore. My only fear is that he might start to associate the front door instead.
I would definitely appreciate some guidance on how to proceed from here with the crating and beyond. I am frustrated and sick with worry watching this behaviour with the female snowball so quickly. He's gone from a puppy who shadows me at home and constantly wants to play to this all-consuming singular obsession. It creates enormous stress for everyone (dogs included!). I've been putting in a lot of effort into establishing rules and boundaries and taking training more seriously. He socializes well with other dogs in public, and his leash walking is improving. Even his recall is vastly better than it was a couple months ago; I can call him back when he's thinking of fence charging the two troublemaking unsupervised huskies the people behind us own -- a huge improvement! Then I'm home and tiptoeing on eggshells.
I'll mention neutering again simply because it's almost impossible to discuss the issue elsewhere without it coming up. I have no particular interest in keeping him intact, but I also don't want to have him neutered for no good reason, especially given the somewhat dubious nature of any supposed health or behavioural benefits. I wouldn't be opposed if I thought he would be happier. I feel like he spends all his home time frustrated and anxious because of a behaviour that is clearly sexual in nature at its base. I want what's best for him, and I want him to be happy. I'm willing to do whatever is necessary to work with him to improve this behaviour before it develops into anything more serious. Hopefully I'm on the right path so far.