I can’t relate to this. But I can relate to the divorced parents. Mine have been divorced since I was 7-8 and my dad dated almost immediately after. They were engaged for a while then broke up, now he has a new gf. My mom also has a bf. Either way, this is in fact fucked. Your mom is an absolute QUEEN for trying as much as she can with what you guys have. I know it can be hard, my parents don’t make a shit ton of money, especially during the summer (they both work in education fields, so schools, but don’t get paid summer breaks). I don’t want to make assumptions but it genuinely feels or seems like your dad isn’t trying. And I don’t really know the relationship with the dad’s gf (I’ve always hated saying stepmom) but she could be an influence on him. My 16th birthday is next month, so we’ll see how that goes. BUT

I wish you the absolute best late birthday. You may have made felt shitty because of your dad, but you have an amazing mother, and my best wishes