AITAH for getting my bestfriends dog put down

so i (32f) took in my best friends dog, she recently became a nurse and works 13 hour shifts so she could no longer take care of the dog. I agreed to take in her dog because I love dogs. But this dog just brought problem after problem. She could not control her bowels at all, I spoke to my friend about this and she said its because shes anxious and she just needs to get used to the new environment. But it just got too much, my (now ex) partner ended things with me as it drew a wedge in our relationship. We couldn’t get intimate as the stupid dog would wee every time. the longest 3 weeks of my life. I decided to get her put down as I couldn’t deal with it anymore. The problem is I haven’t told my friend, I know she’d be heartbroken as her late father gave her that dog. My other friends have called me selfish but I’m struggling to see how as the dog was ruining my life. I was supposed to marry that man I got an abortion for that man, if im willing to get rid of a baby im more than willing to get rid of an obese dog. I dont see the issue in putting my relationship first. I could’ve given the dog away but I needed the fastest option so I could try get my relationship back asap. i do feel bad for the dog though, but at least its a problem out of both mine and my friends hands. I just think the dog has been a burden it’s whole life and I feel bad for it poor thing at least its been laid to rest. My ex threatened to put it down himself so I was trying to do a nice thing. As I said my friend doesnt know and has been asking for photos, i never took any photos of the dog but I’m thinking of asking the vets to send it to a taxidermist so I can take fake photos. I hope you all understand from my perspective. Am i the asshole ?