Question about before the children come?

 My husband and I have his two daughters for a 2 week visitation. They have been with their mothers for over a year and do not have the same type of rules/expectations him and I have for them and our future children together. Him and I are ttc our own children together. These few days with his girls have been very hard on us as a couple but nothing terrible. We are very much a team and everything just flows with us from start to finish everyday. 
We want to figure out how to implement a good transition for couple to couple plus children. Any advise to prepare? And keep our team/duo working smoothly?

step children and bio children are a very different ball game... being a strong supportive couple will help...children will rock you to your core... a few times...

Best advice I can give you is to not argue in front of the children or go against what the other parent is trying to say,teach or desipline the child because the kids will work that against you. Trust me, this isn't easy to do all the time, but for the most part my husband and I are on the same page....I just sometimes feel he gets on my kids from my previous marriage harder than he needs to. It's also hard on me because I can see both sides when my husband and older 2 kids don't see eye to eye....sometimes I feel in the middle! And like Lexa said, step children and bio children are quite different but it's important that the step-parent love the step-children like their own and do their best to treat them the same!

My husband and his Ex have joint custody of their 2 boys (5 & 3)- and sometimes we do talk all together to make sure we are all on the same page as far as to what is going on in each other lives/homes.  We do try to keep her rules the same as ours as her, so there is consistency (she does have them more time than we do).   I do fell that sometimes I am the wicked step-mother because I am harder on them than their dad is- he wants to be the "fun dad" but there is a time that he needs to be a parent and not a playmate.  There are times that I will talk (more in text) his Ex and let her know that something has happened either good or bad- and not necessarily will tell my DH about it- sometime women can understand each other better than Ex's can.