How the hell do you cope with it? 
I've struggled on my own with our four children for years!... I've not had the time or energy for a relationship of my own, I work alot so wanted to spend any (rare) spare time with my children... so he thoroughly enjoys throwing his romantic weekends away etc in my face.
He will text me random messages, carefully and casually throwing in 'did you remember I'm away next week so won't be having the kids over for tea (again)' I don't ask why or where etc as I know it ALWAYS leads to him telling me ALL about how he's taking his girlfriend to Florence, New York, Spain etc etc etc... Knowing full well I work full time trying to make ends meet, I haven't got anyone to take me away, and just occasionally he'll pat me on the head and say "don't worry - you'll meet someone who'll take you away one day" 
If he's ever bored he texts me and does his best to get any kind of conversation going... He'll bring up our past, his regrets etc... I occasionally 'engage' but mostly remind him it's been 10 years, and he needs get over it. He has tried it on with me many times, despite the fact he has a long term girlfriend - I obviously tell him off. I caught him 'flirting' with a co-worker on a busy high street, where anyone could have seen him!
He's just dropped the kids off early today as he "has to get back - I'm taking *** away for the week" Not even checking he's ok to do so, because, well, obviously I won't be doing anything of course 
I don'y mean to rant - but I really have endured years of him casually telling me/showing me his new huge house he just got with his new girlfriend, or their new sports car, or how he's whisking her away to lovely places etc... while he knows I'm either at work, or at home on my own, quite often cleaning up after sickly kids.
He clearly gets something out of making me feel small and alone...
How on earth do I take control over this situation, when I literally have no control of any of it. Why does he want to continuously rub my face in his life?
Do I feel worse because I don't have anyone in my life other than my kids (which I wouldn't change at all!).
Advice would be so thankfully received! X