You are not doing anything wrong! I only have 1 child-15 mos and we're not yet at an age when she will SSTN. We cosleep and nurse so I don't expect her to. She's a baby. Babies are programmed to have their mammas nearby. It is absolutely normal that he wants to sleep near you. Would you want to sleep in a big scary crib? Mine didn't and at first I was stressed about it but then I listened to my instinct and talked to people with similar parenting ideas to mine.
I know the pressure to have a baby SSTN. It's the first question everyone asks. But waking is normal, and eventually they will learn to get themselves back to sleep. Usually she will sleep 7 hours or so then want a snack before going back to sleep (she wasn't doing this before 12 mos though). But then there are teeth coming in, growth spurts, stuffy noses, etc that completely disrupt that-how could it not? So, if your drive to get the kids to SSTN is external, try to let it go. If, on the other hand, you can't take it anymore there are methods to help them.
Ferber is not the only solution. That method makes no sense to me. I am available to my baby when she needs me all day, I don't understand why night should be different. Babies cry because that is the only way to communicate at that age; I don't want to teach my daughter that I will ignore her needs. There are other techniques. Check out the book "No Cry Sleep Solution." Pantley is the author, I believe. She is a mother of several children, not a certified sleep expert, and has some methods that many people find very helpful.
I think there is nothing better than snuggling my baby at night. She probably feels the same way about it. If you are away from the kids during the day, and if your husband is traveling (mine is away a lot so I can relate), then it just makes sense that the kiddos would want physical contact with you at night. I also can't believe my baby is 15 mos already and know that everything changes so fast.