<human>: Can you succinctly summarize the text in 1-3 sentences?

Dear Reddit,

Here is my situation: 

I met a great girl and we fell in love. While it has been a short relationship, it's based on an honest and what feels like a solid foundation. Even though we've known each other for less than a year, I know that I want to propose to her. So , the plan is to become a family. In fact, it feels like just a formality and we both discussed it openly. We can marry each other, but it's not a necessity just to satisfy a social form. I'm stating that to outline our intentions and their overall impact on our family's stability.

Having said that, my girlfriend (let's call her Alice) has a wonderful daughter. Long story short, the father didn't want her ( by this I mean both ). There were financial issues, regular arguments between them in the past. 6 years have passed and currently he has visitation rights. Daughter loves him of course. Yes, that is a good thing. The daughter has also accepted me as a stand-in, friend, step-dad figure. We get along great.

Now, we now have a baby on the way and I simply can't wait. I'm asking for advice about juggling both roles and being the best step-dad to one and best father to the other child. Ideally, I would love to be a father figure because as I see it, being a biological dad but not fulfilling father duties is wrong on his part. I just don't want to wedge myself between them. I am getting opinions from my close friends, but I've seen much wisdom come from reddit community. Well, sometimes the pun threads get tiring, but I wouldn't expect anything else.
<bot>: I'm asking for advice about juggling both roles and being the best step-dad to one and best father to the other child.