Isn't your GF 20 yrs younger than you? It's pretty obvious in her actions and what she says.
Look, she had no qualms about dating you before you were D from your W. She had no qualms about sleeping with you, or moving in with you. Right? So, when she says she is embarrassed to be pregnant and single........don't believe it. She is a girl looking for a secured future with a guy who has a good income. I don't think she's going to be in any hurry to get a job, b/c she'll expect you to take care of her.
Yes, she is certainly punishing you by not cooking and keeping the house (if she's physically able). I think it will get worse. She's playing games, to apply enough pressure to get you to the alter. If you marry her, your life will radically change for the worse, and I'm not talking about the baby. I'm talking about what kind of woman she will become. You will see a side of her you didn't know was there. The persona you saw when you first moved in together, is not the real person. Don't be one of these men who gets stuck with a woman, thinking one day maybe she'll be like the girl before the M. Her behavior toward you has been changing ever since she announced the pregnancy. You better take it as a serious warning, Wolf. Between your XW and GF, and the problems it's going to cause with your daughter having such a young step-mother........your life will never be free of drama.
May I ask which one of you were responsible for birth control when you started sleeping together? I think your answer is important.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!