I'm talking to another girl.
Is it a problem for you to talk to other girls?
It is not, but I'm worried about my pregnant girlfriend because she gets worried when I talk to other girls.
There's nothing wrong with talking to people outside of your relationship. If you feel like you are attracted to them or want to cheat on your partner, you should be honest in your relationship.
I agree with you but I'm starting to become unattracted to my girlfriend.
If you don't like the way your girlfriend looks then you need to get over it. If she's pregnant with your child, it shouldn't matter what she looks like right now because you need to be there for her and the baby.