Hello.
What you're describing is typical of a beginning relationship among young people. Neither of you knows how to communicate your feelings in an honest, caring way. Now that you have a child on the way, you'll need to acquire this skill ASAP, because you'll both need each others' support and love more than ever.
Most of us get the idea that just because we love someone, everything will be "happily ever after." In fact, nothing could be further from the truth. Relationships need lots of care and feeding, i.e., honest communication. This doesn't have to be a chore. In fact, once you get the hang of it, it can be lots of fun and can contribute to a feeling of intimacy and strength.
So drop the attitude and ask your partner for a chat. Talk to him in a non-confrontational way about how you feel. And only use "I" statements. That means instead of accusing him of things, you tell him how YOU feel when he treats you a certain way. Don't attack him--all he'll do is defend--and then you don't have a relationship; you have a war. Here's an example of honest, non-confrontational communication:
Honey, when you mock me, I feel devalued, and I also feel afraid you don't love me. It feels really bad when you do that.
Don't be angry; be concerned. The key here is to get him to open up to you in the same way so that the two of you can figure out how both of you can make this better. Remember that in relationships, no one's feelings are wrong. He may be feeling defensive because of your approach. Or he may not have any experience taking criticism. Either way, the two of you need to work this out so that you child will be raised in a happy home. If you aren't able to talk with each other, you might consider finding a counselor who can help you do so. Best of luck to you. Dr. J