My Ex-Girlfriend Is Pregnant For Me But I Don't Love Her

A young man Freddy is in a fix;
I don fumble mehn. Some lady came over to my place to sleep over. As usual things went down that I couldn't help but "release" in her. [Later] I bought her contraceptive pills to use but it turns out that she didn't use them. Now she called me to tell me that she hasn't seen her period for days now and we did it first Friday of this month.
I am so confused because I have a new girl I want to marry and i am truly in love with this girl I want to make her my wife. I'm worried because of a stupid choice I made by sleeping with an ex without a protection. 
Now she wants to keep the baby which I am cool with. My concern is that her people will want me to marry her. I cant marry a woman that I am not in love with.

What do i do? What do i do? I don't want to marry because of circumstance. 
This lady intentionally forced herself on me to sleep with her and I was drunk...when this happened. I don't genuinely love this girl. She is someone I am not even proud to show the world. The girl I want to marry comes from an affluent background just like I do. 
How do I handle this?