Separation Anxiety

I am sorry I haven't written in a little while. It has been a bit hectic in my house the last 3 weeks. I've told you how my daughter (Jacquie), her boyfriend (Steve) and my grandson (Trystin) had moved in for a while. Well Steve has moved out. They had a big fight and decided to move on. That's all fine and well, but you see, now Trystin stays with Steve on the days Jacquie goes to school and or work. I know that's the right thing to do, but I miss him (Trystin) something awful.
He stays overnight 2 to 3 times a week. I guess I should be happy that he is still living here with his mom.
I just plain love this boy in the worst way. I actually have cried when he has stayed with his dad. Now that is silly, isn't it?
His mom has been talking about moving out on her own. She says when the new baby (Nichole's baby) comes, it will be too crowded. She is right in a way, but I told her we would figure it out. We only have 3 bedrooms in this house. I think I'm being unrealistic. She is right.
Has anyone went through this or something like this? Can you give me any advise on how to handle separation anxiety? I have it bad!