My SS4 and SD7 both cosleep with me and DH. SD7 has a bed but doesn't really sleep in it. Sometime she does with me, but I always end up being left alone in it. I don't mind being left in the bed because I get all the room to myself. They only stay on the weekends. DH said it's hard on them going back and forth and is comfortable sleeping with him or us. Should I be more understanding? He said it wouldn't last forever. They also cosleep with their mom as well. 

When you are with your spouse and he/she has kids, but you don't or you both don't together, does he/she refer to them as "his/her children" or "our children" meaning both of y'all's since you all are a blended family?