Don't feel guilty about missing your time out, you the single parent doing all the hard stuff we all need time out.
I hope the ex situation gets resolved very quickly so you and your son can get back to some normality. Routine is important for you son as well.
I would totally hire a baby sitter for a weekend, or see if I could switch/share a weekend with a friend.
Your happiness is important too.
My one child stopped going to her fathers three years ago and I still grieve that time....
Do you have any feel for how long his 'outta country' ordeal may take? Sometimes it is easier to get through something if you concentrate on knowing it is only for a certain period of time. Meaning - are you confident this issue is temporary and things will be back to normal as soon as his court problems are settled? If so, I would concentrate on that.
In the meantime, is there any compromise? It looks like your children are older so maybe it is possible to arrange one overnighter per month, etc? I know it is not what you are use to but it will help pacify your needs in the meantime?
"You never know how strong you are until being strong is the only choice you have." ~ Bob Marley