I have 3, two boys 9, 2, and a girl, 5. Truth be told, only the 2 year old is my biological child.

I would not say I "connect" with them in the way my wife does on any level. My wife is very sweet with them, very loving, and indulges all of particular ticks, which kind of drives me crazy. In my opinion, way too soft. The 9 year old still likes to cuddle at night with both of us - are you kidding - and she totally indulges this.

Concurrently, if you asked my wife, I'm sure she would say I'm far too strict with the kids. I can be quite forceful with them, and I don't do well with excuses or lies. Oldest step-son has learned and is an honest kid. Step-daughter, whom I'm probably closest to, is the most difficult and I'm usually disciplining her the most often.
Little one is just a shy, sharp kid, not a lot of tantrums or blow ups, but also not much in the way of personality, much like me as a kid. In a family of LOUDS, he and I are the quiet ones.

The point is we relate in totally different ways. To her, the kids are her special angels, and while I certainly love them, there are times when I see them as selfish, indulgent, mess machines that don't listen to shit. Still, when it comes to physical stuff, i can't pull my wife off the couch but the kids love to run and play outside with me.

So i would imagine your resentment is linked to the fact that he doesn't help you, which really is bullshit. You're a team and you should be able to depend on him. I do a lot of work with the kids, feeding them in the mornings, dropping them at school/daycare, putting them to bed; my wife will cook, clean, do laundry, pinch hit for me with the kids. Lots of shared duties.

Keep in mind that the first kid is the hardest because you haven't learned how to give so much of yourself up yet. 80% of my day is either dealing with the kids, dealing with a mess the kids made, or dealing with work. Prior to kids I'd say work was 40% of my day and nothing on the weekends. That's a lot of me time to give up, you know? It can be tough.