My (27M) girlfriend (31F) is divorced (amicably, he came out as Gay) and I've all but moved in with her and her son who I will call Jason (11M). We've been dating for about a year (known each other for longer than that) and I've been picking up her kid after soccer while she's at her job late some days (Pediatric Dentist). He isnt interested in calling me Dad but he DOES call me Dude (he says it sounds like Dad but isnt dad because im "Just A Dude"), he's a great kid and I love him dearly. Jason's 11th birthday party was this past week and my girlfriends father pulled me aside and asked me if I would stay out of their Familiy Photos, a tradition they've been doing every year since he was born where they take the picture in the same group pose so they can all line up in their album. Now, I thought I'd be real funny and photobomb this with a funny face and a peace sign, and while Jason and I were both giggling afterward my FIL was not. They did get the family photo later, even after I went and asked him more formally if i could be in it (I was declined), and I have to say it did kind of get under my skin a bit. I had been pretty much living with them for some time now and it really stung to be formally uninvited from a family tradition centered around my kid. This ended up hitting me harder than I expected honestly and I was morose and silent throughout the rest of the party. Now, her dad seemed like a really good guy. However he was not at all happy with me now. He pulled me out to the back porch and yelled at me about how I was so disrespectful to family tradition that started when my girlfriends mother was still alive (She passed away during Covid) and when her sister (older, adopted when she was a teenager, moved to Germany a few years ago) was living with them. I had not been aware of the severity of the situation and started crying and apologizing. It was loud and the neighbors 100% heard it. Its at this point my girlfriend comes out and she sees her dad yelling at me and me crying. She was very angry at him for how he was treating me behind her back and he ended up leaving in a huff. She was very mad at him but also at me for starting a scene over something that she thought was so silly. This is my question. I wanted to call him to apologize for the way I acted. My girlfriend, however, when I asked her for his phone number didnt want me to. She said I didnt do anything wrong, and I didnt know the situation at the time, and that he needed to have someone not bend over backwards for forgiveness just because of a disagreement. I understand that she feels like that but her dad already isnt 100 percent on me. I work at a weed shop, and he's given me stern warnings before about the kind of long term responsibility he expects from me if im going to be his grandkids' parent. I don't want to go behind my girlfriends back when she has expressly told me not to apologize. So I guess I have to ask: Am I the asshole for still planning to? EDIT: alright this one is on me theres a critical piece of information I seem to have neglected to have explained properly - we have been friends for 7 years (including before she was divorced, i was in contact with her when it happened) and I've known Jason personally for a similar amount of time. We've only been OFFICIALLY dating since last September. She has also spoken to me once before about getting Married [This is scary as fuck to me so to be perfectly honest i gave her kind of a noncommittal non answer i admit] but I am not some weird stranger digging into someone's family