My honest answer would be to move on...
Obviously, you both had something good together, and ofcourse you will both be comparing other people with what you have had with partners since.... but i think you shouldn't put your life on hold and see what happens... she has someone out there, your the single one. you have worked hard to get the money in the bank so to speak, use it, enjoy it and get out there!!!
she finished it with you, and i would most definately travel the world, see the sights. she has children but ok, they are not yours,... so you have no committment towards her on that side... im sure you thought a lot of her kids too... but as your in a position that you are not tied or have your own children yet, well do it now... travel, see the places you want to see....
who knows, maybe one day you will both get back together, but i think in time you will meet someone out there who it will all feel right with again....
good luck xx