How do you deal with weekends apart from your children? 

I am the non-custodial parent and I hate not having them here with me every day.  But, when I have them, I spend time with them.  It may not be going anywhere, but I'm here, with them.  I can't afford to do much for them right now.  I'm in school and I don't make much money.  But, just talking to them and being their support is what I know I can do.

My kids are a little older, so we talk about things, such as dating, school and spiritual things.  When we go to church, I try and talk with them about the message.  That draws us closer, too.

You hang in there and just continue to be the loving, supportive mommy you are.  They will know.

I completely understand how you feel - I have 5 year old twin girls. Until the divorce that was forced upon me.....I had never been aprt from them...they had never had a babysitter or even stayed for an hour with a grandmother. The first time my XH drove away with the girls, I felt all the oxygen had been sucked out of the air. Within 7 months he took them to a family reunion for a week - I honestly could not imagine how I could get out of the bed when they were gone. Things have gotten much better for one reason - I utilize the time they are gone doing things to make the house & their lives better - I do all my cleaning, grocery shopping, & errands while they are gone....so I can devote the days they are home to playing games with them, reading to them, sitting in the playroom & watching them build elaborate forts, etc. By using the time they are gone to actively make life better for them, I feel less desolate, more productive & proud that I am working to give them a good life. If they are gone for more than a couple days, I buy them small gifts for each day & hide them around the house, I make a treasure map & we go on a treasure hunt when they get home. If I get particularly lonely I try to remember that my loneliness is a sacrifice I make for them.....little girls need to be with their dad to have happy, full lives.....I would never deprive them of that fundamental right.  (yes I know some dads are dangerous & the children are better off protected from them....but I am talking about the average situation when the X may be a jerk but he is kind to his kids.)

Sorry, I don't know what happened that my post is so scattered... maybe it was my ex jinxing my mind...lol...

Hic is right; as impossible as it seems now, you do get used to ALL the changes, wanted or not. initially left (ten yrs ago) he was the best daddy ever, trying to make up for all the time he didn't give them prior to taking off. I missed them painfully but I was happy they were getting their daddy's attention; they were so happy feeling loved by both their parents. they knew they mattered. I know, how you feel, but perhaps trying to remind yourself how important it is for your daughter to have daddy in her live would make it a bit easier. If I can suggest only, try not to overcompensate her when she returns, it's natural to want to but in a long run it is not going to be to her benefit. 
My ex doesn't long to spend time with our kids except very occassional couple hours, but when he had left the first time he became most attentive, hands on daddy and although I missed kids painfully, seeing them happy, knowing they felt they mattered, made my missing them a bit easier.  Soon I started actually looking forward to 'me' time; I spent hours at the gym and took some personal interest classes at the local college, I enjoyed time with friends and went to the bookstore a lot. For longest time, evening thru night to morning stretch was unbearable; not being able to check on them at night, not cooking their breakfast, that was so hard, but you get used to that too. It's okay to cry and miss her, you must give yourself time to adjust but if you do get a chance try to go out and do something simple that gives you - grown woman, not your child's mom, pleasure and joy. And please, please believe me Hanna's Mom, it does get easier. Hugs to you.

You get used to it.  You find things to do for yourself.  It will be hard for the next few months, but you will adjust.  Welcome to the wonderful world of divorce with kids.