How would you feel if your boyfriend went to his ex girlfriends house instead of home?

For context my boyfriend and his brother got into a hit and run car accident 4 days ago. A drunk crashed into them and fled the scene by his brother wasn't wearing a seatbelt and went through the window shield and he died. I didn't even know because I didn't hear from my boyfriend until I got a call from his phone but it was his ex girlfriend. She told me he showed up to her house covered in blood and class. He was in shock and wouldn't talk so she called 911. They did catch the person who did the hit and run and his brother is getting a memorial service Friday. My boyfriend was in shock for a while and would not talk. He started crying before he started talking. He's talking now and back at home. I'm not trying to make any of this about me but would you be hurt if your boyfriend thought to go to his ex girlfriends house over the home you share together and have tried to grow a family together? My step dad thinks it's because we just moved into the house and it was a 3 mile walk vs the ex girlfriends house being right up the street and he probably just recognized the area in his shocked brain. I just feel so hurt by it and I want to know how you guys would feel?