Fiancé doesn't understand 😔

So my fiancé and I have been together for 6 years, and yesterday, he bought a motorcycle without consulting with me first. He didn't spend our life savings on it or anything, he's a mechanic and got it for free from work. It's just some 250 Yamaha something or another. But I am very unsupportive of him riding it. Normally, he is extremely supportive of me, in supportive of him, and we really feed off of one another. But this is one thing that I just can't support and he doesn't understand. Mi grew up in a family of riders. Both my parents ride and so does my brother. Well my dad, who was a very safe rider for 30+ years had been in an accident about every 5 years. Never anything too serious, but he did shatter his knee and has had a few stictches in his head. No permanent damage though. Until 5 years ago when he was struck by a pickup truck going 75 mph on the freeway and was killed instantly. Since then, I am a nervous freaking wreck about motorcycles, and my fiancé knows it. He has dozens of hobbies while I stay home and raise our son, so I figured when I told him how opposed I was, he'd be willing to give up one hobby for the sake of my sanity, but instead, he has been very adamant that he is going to be safe, and actually rather angry and defensive over the issue, even though he's never actually rode one before, he just thought it sounded like something he'd like and figured he'd give it a try.