Needing to vent

How to partners in a step parent situation deal with frustration? My BF acts like his kid can do no wrong sometimes. He’s defiant, disrespectful when he’s told no or doesn’t get his way and if there’s an altercation between his son and mine, mine gets the brunt of the yelling because he’s “older” by 6 months. It’s complete bullshit. He says he loves my two but will pick any little thing they do apart sometimes when he’s in his OCD mood. Yes he has anxiety and depression, yes he has a military background where he wants things picked up and organized, but f*ck, kids are kids sometimes and they’re ALL TO BLAME. They ALL act up and cause trouble. It takes more than one one person to fight. You’re child isn’t a saint. I love them and treat them all equal: you act up, you get in trouble, you talk back you’re in trouble. You help out and do as asked you’re praised and rewarded. You’re talked to in a loving and respectful manner. I will hug and kiss you goodnight equally. Yes I hold my kids closer to my heart but I won’t make my “step son” feel any less mine than my own. I don’t believe in that. Apparently I’m the only one. I just get so frustrated. My kids are good kids. They deserve love and affection, understanding and respect too.