Fist off hello and Welcome to families
I agree with Jo (mollymae). I too was PG very young and had the option of 'getting married'. I chose not to ask I felt a baby is not a good excuse for getting married. I am so glad that I chose not to....other wise I would have been in an abusive and unloving relationship. Now I am married to my soulmate and I have no regrets in my choices.
If you don't love your spouse then let him go. Let him find someone that will love him unconditionally. He deserves that....and so do you. You don't want to show your children that settling for an unloving relationship is normal and that they should be happy with whatever life throws at them. This is not a healthy thing to teach your child.
You children may be too young now to understand BUT they will understand when they are older. Children are far smarter then we give them credit for.