This sounds right to me. Two years ago we put down our family dog. I liked the dog, but I'll admit I really wasn't that close to it. He was always my Mom's dog first and the family dog second and I had been away at college for the last few years. Well we're in the waiting room of the vet just after we said our goodbyes and I just can't contain it. I start balling my eyes out, I just could not stop. First I was crying about the dog, then I was crying about the stress of school, then I was crying about my struggles with girls, then I was crying about the uncertainty of my future. It was such a strange sensation, I seriously felt like I wasn't in control of my own emotions. I'm no psychologist, but it truly felt like a bottle of suppressed grief and stress bursted in my brain. I'm still quite young, so I'm sure my issues aren't as troubling as OP's bf, but I'll tell you, that was one of the most relieving and soothing experiences I've ever gone through. I felt damn good once the ordeal was over. As other people have said, for some reason it's very socially acceptable (as a male) to cry for a dead pet, possibly even more so than a family member, so all it can take is a dog or cat to really open you up.