I really don't think any of us should be judging you, but I will give my opinion mostly on the name issue. I do go on and on, but I'm just giving my rambling opinion, whatever that's worth. I really don't follow some of this idea that naming rights should belong to the father. That whole tradition is only because we live in a paternalistic society that sees family as male centered. Yet when things go south it almost always ends up being the female that takes care of the family. Men seem to think that because they were once the bread winners that automatically should entitle them to last name of child and spouse, family ownership, and decision making above the spouse. I hope most families are past this, but I know many are not. Buy the way I and my kids have daddy's last name, but that may be more because I was anxious to get rid of my maiden name (which was Gronvold now I have short and simple Brown.)though we are married and never had any cheating issues.
Usually when I hear a child's last name, I tend to associate it with his families name. So when mommy is the full time care giver and daddy is either always missing or sometimes missing (to go make other babies without your knowledge or otherwise)I do tend to assume that the child's last name is the same as whoever is at home caring for and about them all the time. In your case that would be your name. I know there are many reasons for many different last names, but that tends to be my first assumption until I am explained otherwise. So if daddy still hasn't married you and doesn't intend to marry until after baby is born and cheated on you and had another child with or without your knowledge, it seems as though you are much more a part of that child's permanent and constant family then a daddy that hasn't completely decided to stick around. I know I'm probably just confusing you more, but I see this more as the female's decision and you should make the final decision on the child's last name cause you are far more likely to be a full part of that child's life. Why do we give men this privilege who have proven to only intend to be partially involved in the child's life while the mother has always been fully involved in the child's life (I'm not referring to mothers who are only partially involved themselves, nor am I talking about men who are fully involved). There's nothing that says the child has to have the dad's last name, other than tradition and tradition is changing and probably should change a bit.
Someone asked "what happens if something happens to you?" but how is that relevant? You could ask the same of him if the child has his last name, "what if something happens to him?" The name doesn't matter, the parents can still be included on the birth certificate without giving the child the fathers last name. The child's name can also be changed once daddy steps up and decides to fully include himself in the child's life.
If you are still conflicted about making the daddy feel bad or excluding his last name you can do as many have suggested and use a hyphenated name so both are included. This often allows the person to decide what he or she wants to go buy weather it be full hyphenated version or just male or female half of last name. I also agree with you that having kids with multiple last names especially for children with same set of parents can be confusing for the children and for others who don't know your full situation. It can also leave the child feeling singled out or different, then the others. It may also increase unwanted questions from others about the paternity or maternity of each child, which you and your children may or may not want to discuss.
I just think these things should be yours and spouses decision. But it should always be a choice, not some automatic thing that is always for the father's entitlement, especially when some fathers don't take full responsibility as a real father. As I said though, this is just my opinion, whatever that is worth.
