My wife (24f) is a stay at home mum of our daughter (1f) and is struggling with her mental health, especially since I (28m) have started to work away from home about 50% of the time and will be abroad 7-10 days at a time. She loves staying at home with our daughter, but is feeling isolated a she recently moved away from family and friends for my job, she is depressed and due to something that happened in her past, struggles with extreme anxiety being alone in the house at night (she is going to therapy).
She really wants to get a dog, which I am definitely open to. I really would prefer a smaller breed, but she has her heart set on a a Saint Bernard as she grew up with one and adores them. Against my own wishes I agreed on the condition she pays entirely for its food maintenance out of her own money (she has her own little business she makes a couple hundred pounds from every month). My wife was absolutely ecstatic, picked out a puppy she wanted and last week we went to go and collect it. The puppies were adorable, but when I met the mum and saw how big she was I got cold feet, pulled my wife aside and told her I'd changed my mind. So we went home without the puppy.
She initially took it better than I expected and left the breeder's without a row but in the days after her mental health has deteriorated further and I'd be a fool to not see that this is causing major resentment in our marriage.
I feel like such an AH and know I've really hurt my wife by literally pulling out when she had the puppy of her dreams in her arms. I'm just not a fan of big dogs and don't want to live with one. I'm still happy to get a small dog, but my wife says she wants a breed she knows and loves, and a big dog would help her feel safer when she's alone. She doesn't want to comprise.
Am I being unreasonable?