It depends on the circumstances, how long ago was the divorce, and whether the parties involved have matured or not and the new partners are understanding, etc.
I have a couple of friends whose parents divorced and remarried and had joint custody and everybody got along seemingly well. Not perfect, but then, not even your blood family relationships are ever going to be perfect and trouble-free.
It is very normal to me because I was raised this way, and my dear families are sometimes a confusing mix of halves and steps and in-laws as well as full blood relatives…
My dad married young and divorced young. Before turning 30 he was divorced with two young children. A few years after his divorce, he met my mom, whom he dated over 7 years before I showed up and they married.
During those years, I guess some of the anger and resentment over the divorce eventually faded. Mom is and was very pro-family relationships, so she made sure dad didn’t slack in any of his duties. Dad, as grumpy as he is, really enjoyed his children, and was a good dad to us. When my (half) siblings were young (before I was born), my mom and dad would take them on their trips to visit my mom’s side of the family, which included nephews and nieces the same ages as my sibs… So they all grew up together and knew each other looong before I showed up.
When I was a toddler, the resentment had decreased even more, and my sib’s mom and granny baby sat me for many years while I was in primary school… To the point that some of my teachers thought she was my mom because she picked me up so often…
Time and illnesses have passed and have just strengthened the bond between us. I also grew up with my sibs’ younger cousins, who are closer to my age than they are. When I last visited home, I spent time seeing my sibs’ granny (she passed away a few weeks later). When my sibs’ mom needs a car ride, my mom always offers it and gives it. A couple of years ago, mom was admitted to the ER due to severe anemia. My dad, at his wit’s end, had nobody else to call but his ex. She came without hesitation, and took care of mom while dad was busy working. She did it once more, very recently, when mom’s condition returned. When this spring I graduated from vet school, my sibs’ mom was there, celebrating with my mom and dad, and proud as well.
As another example, my grandfather widowed in his early 40s, dated a few years, and married a sweet, smart, funny, great woman 4 years after his first wife’s (my bio-granny) death. They remained together for 40 years, until my grandpa’s death almost 4 years ago. This woman (dad’s stepmom) is the only granny my cousins and I know, the only one we cherish, the one we love and respect (none of us were born when bio-granny died).
Granny, for many different reasons, found another love in her life that made her happy and smile and gave her company and solace. They married about 3 years ago, and invited both families. My dad escorted her and made one of the speeches. Relatives from bio-granny and grandpa attended the wedding and if not they gave their blessings, even (40 years is a freaking long time).
Now, my (step)granny’s new husband (step-step-grandpa?) is not my real grandpa, nor will he ever replace him. But I have to admit I like that granny has found a decent man who cherishes her and loves her and treats her with respect. And the man is funny and witty and has some quirks which remind me of grandpa. And I like him.
Remember the OP is also asking if it is normal or not… And I say it depends on the circumstances. (Step)Granny was a divorceé when she met my grandpa. Nobody has heard or known anything of the sorry ass she married before grandpa. 