Since you are married he should not be able to kick you out of your home or apartment. In addition, since the decisions, we make when we are young set the foundation for the rest of our lives it might be worth just trying to have a conversation about this with him. In his case, perhaps you can talk to him about how having each other retains stability and security that you both can rely on in your futures -- emotionally, physically, and financially.
Ask him what benefit getting a divorce would really have for him or your child. Bouncing around from one relationship to another really does not add any real quality to a person's life, male or female. You might want to give some time for any fighting to simmer down and then approach the topic.
Since he is married to you he is already in a serious relationship and having second thoughts about that in itself is not a reason to dissolve a marriage. Husbands and wives have frequent disagreements, differences of opinion, and sometimes temporarily regret getting married because of this. While we can't force someone to love us, if he is willing to have any kind of discussion about saving the marriage, there could still be hope.