My daughter spent her life waiting to find her real dad. It's been a few years since she finally met him and she texted me a couple weeks ago telling me that time wondering who he was and where he was such was just wasted. She said it's been nothing but disappointment and let downs.
So what I'm saying is you and your youngest need to live your lives. It's true the father needs to be a man and do the right thing by being there for his child, but you can't make your youngest miss out on the opportunities in life waiting for someone who may never come around.
BTW, the end of the story is that my daughter said through all that work of trying to get to know her biological father is that she really learned to appreciate all the years she and I spent together.