It can be successful, indeed it can be wonderful. But my own experience is that it can be a very long and painful road also.
My mother remarried when First brother was about 12, I was about 10, First Sister was about 7. My stepfather brought in his child from a previous marriage, my Second Sister, who was then about 2. My father remarried twice, one fairly short marriage when we were about 13, 11, and 8 and then again some years later. My father’s third wife was a keeper and she had two children, one about my own age (then around 18 or so) and one about 10 years old. In the meantime my mother went on to have Second Brother and Third Sister. So we had, in this fairly ordinary situation, 5 divorces affecting a total of 9 children and 6 adults.
My stepfather was confronted in the beginning with two children (first Brother and me) who were lying in wait for him to try to pull some kind of paternal bullshit. Happily for us all he was not inclined to step into that trap and just waited. He wielded what authority any family member adult might wield and otherwise just waited for us to be ready.
My stepmonster (Dad’s first remarriage) had many nightmare days with us and now that I am an adult looking back I think it really was not pleasant for her – she wanted very badly for us all to be like the Brady Bunch or something. She had no notion of boundaries and just started right in acting like Mom. But we already had a Mom and while we were not always entirely happy with her, we at least knew her and she knew us. But the stepmonster lost us entirely when she approached my mother and asked if they could have custody of First Sister because the two older ones were just a lost cause but there was still hope for First Sister. In front of us and without discussing the matter with my father. She never did figure out why everyone in the room except her was not best pleased with this move.
My second stepmother was jewel, a prize. Of course by this time we were all somewhat older. She simply said that she was our stepmother, not our mother, and that she was very happy to be that and asked us what we thought that should mean. After she passed on, my father raised her son through the remainder of high school (much to the chagrin of his actual father, but he got what he played for) and they are still very close. he is now, lo these fifteen years or so later, in the process of becoming my Third Brother. Our kids are very close and consider themselves cousins and so the process of blending goes on.
Of my three stepsiblings and my two half siblings (we, the first three, call them the mergers and the acquisitions sometimes – lovingly we call them that) I refer to three as my siblings and almost no one in my life has any idea what the real blood relation is. But they are my siblings and the blood relation is irrelevant. The two who came to us later in life I do not consider my siblings, mostly because we did not grow up together. However, my stepbrother currently shows that he wants to be and remain a member of the family and there is a chance that we, though we did not grow up together, might still grow old together and it would not surprise me if at some point in the future I start calling him my third Brother. I remain open to my stepsister, but she is very busy just now with her own life and doesn’t feel the need to be blended into this creation we have made of our blood, sweat and tears, as is her right.
There was much quarreling in those couple decades; many tears, a good bit of emotional pain, more than one day of despair. A certain amount of therapy at various times. But you just have to keep talking, keep reaffirming your commitment to this family whatever form it might take in the end, keep your eyes on the boundaries and be aware that you have a whole lifetime to get there. It’s unlikely that there will be a moment when you can point and say “Here, this is when we became a real family”. You just look around one day and it happened.
In some families it doesn’t happen that the step parents become as parents; my own parents never aspired to that even though in the end they did get it. They took the position that a stepparent was also an important person and not a aspirant-to-parenthood. That the love of a stepparent and the care of a stepparent is in its own way special and profound – an uncle or an aunt or a grandparent is not an aspirant-to-parenthood either, being just like a parent is not the Big Win Window. It is a relationship that has to come form both sides, freely, or it won’t come at all.
Two of my stepparents agreed and one did not; you can see above how that turned out.
Don’t worry that one will feel short-changed; what they all want is an even playing field. One thing which worked well for Hubby and I is to discuss any and all family issues behind closed doors before presenting it to the Gang of Four. Maintain that unified front. If an issue comes up in the middle of Family Discussion, take a time out and confer with your wife about what’s going on. Once they see that you are serious about being fair then they will come around.