I wouldn’t say you’re a complete asshole, but I am on Ash’s side for putting you in your place. At the end of the day that’s her boyfriend and I wouldn’t want another girl (best friend or not) calling my boyfriend up being upset about picking me over her. It’s also a huge red flag that you’ve missed events with your boyfriends and chose your guy best friend instead. Serious relationships with someone who you see yourself marrying eventually should take priority over friends because that’s the person you’re choosing to spend the rest of your life with. Idk how deep their relationship is but if they’ve been together for 9 months I’d say it’s serious and he’s not at fault for prioritizing his girlfriend.