Absolutely 100% categorically this.
You made her pregnant when she was only 17. This was a result of your actions. An effect of this is that her adult life has consisted of nothing bar you and being a mother to your child.
I'm sorry but your responsibility here goes far beyond you deciding you are bored with her and want something different from life now. I don't think, morally, that you get to make those decisions now. You changed her life and should stand by her.
Whether you might get bored and want something else is something you should have thought about before making a 17 year old pregnant when you were 22.
When you have a child everything changes - its no longer about you, its about your family collectively. Thats why many of us try our hardest to avoid having one in the first place, let alone with a girl who at the time would have been much less mature than you.