Being ashamed of you and your daughter is not something I would even consider. The first thing I would think was happening is that he's not free to have you known to his family. I suggest he's married.
I also would think his family is aware of you and is going along with his charade. How old are his children? Surely they know you're pregnant and live with him. They will talk about you. Doesn't an adult drop them off, come in briefly?
Is he fulfilling his responsibilities as their father; paying child support, co-parenting with their mother, having them with him on a schedule? How he parents his children will tell you how he will parent your child.
You've been involved with him 2-3 years and you don't know anything about his relationship with his family? He isn't sharing his life with you. Why have you been OK to just share a small part of him?
You haven't given enough information for me to do more than guess what is going on. What stands out is you thinking you've done something wrong, that he's ashamed of you. Sounds like he's abusive causing you to see him as better than you. To remain all these months accepting that he hasn't been honest about you is an indication that something is very wrong with yours and his relationship.
I suggest you put your life in order so that you can leave if necessary and then insist he give you honest answers.
I suggest you are being psychologically abused. I urge you to talk with a counselor to help sort this out. Get help from a women's shelter. Start making a plan in which you aren't totally dependent on him. Even if you stay, having some independence will help you feel stronger and more in control of your life.