Bonded Pair HELP

Alright so I have a pair of cockatiels, male and female. They’re super into each other and have become increasingly hormonal. When I’m home, I usually will leave their cage open while I’m upstairs and let them hang around but recently they’ve been crawling BEHIND THE FRIDGE to find a nest site. Just imaging trying to get them out and how unsafe this whole situation is.

For now, I’m not letting them out of the cage unsupervised because they will try to make anything a nest site in any crevice they can find. Male also gets extremely territorial around female. It’s been a nightmare to say the least.

I’ve tried everything guys. I even paid a bird behavior consultant to see if there was anything else I could do to help with their hormones. NOTHING is working and I will not separate them. I’m thinking at this point maybe just saying fuck it and placing a nest box in their cage could be the way to go because they’re both sexually frustrated, getting themselves in dangerous situations, and are spending more time in the cage which I hate for them. My logic here is that letting them live out their biological imperative could be good for them overall.

I have a person who owns a prominent parrot store/rescue where I live that would happily take the chicks off and hand raise them shall my birds procreate. I also have an avian vet literally next door in case anything goes wrong. My biggest concern here obviously would be potential egg binding, but I’m starting to think that the potential of that happening is not as bad as their current situation where they’ve already gotten in serious danger.

Anyways wanted to see if y’all have any other words of advice, or if I’m on the completely wrong track here. Anything will help!!!