NO, you are not ALONE, you are free of that idiot, and you have a wonderful DD to show for it.
How old is she btw? It gets easier with DC you know?!
Your immediate problem is feeling lost when she is with her dad. OK then that is your time! You have 5 hours to do what YOU want to do.
FGS woman 5 hours! on a Saturday???? Get thee to the shops, to the cinema, even if it's on your own it'll be an adult break! Go to the hairdresser/nail person whatever. Look for things to do that will lift your spirits!
If money is an issue, give YOURSELF a spa afternoon! facepack, long wallowy bath, primp and pander, cosset and treat yourself! Go for a run... stick on a DVD, you get the idea!
You are in mourning at the moment, grieving the loss of a relationship. Not for the X himself, but more for the what ought to have been, how it could have been, but never was, and now never will be. It's the death of hope for that notional and imaginary relationship that saddens you most.
You think that the breakup reflects on you? Hardly!, it reflects worse on him, that he couldn't keep his family together, that he couldn't shoulder the responsibility of a man, like a man.
Don't look at this period of life as the be all and end all, it so is not that. You NEED time to lick your wounds, to gather yourself and your strength and to learn what you will and absolutely will NOT accept. This is a very interesting and important part of the rest of your life, and also a crucial part of your NEXT relationship.
This sad phase will not last, it literally will have to give way to something else. To the rest of your life!
You ought to be excited that you have the chance to work out who you are now, and plan for who you can be in the future!
Is there anything you have wanted to try? a course or something, there is your window opportunity. When you are happy and contented in your own skin, not worrying what value some bloke places on you, believe me, you will be at your most attractive, but more crucially, you will be at your most choosy, and you will not make the mistake of picking a carbon copy of the idiot you just escaped from.
Onwards and upwards dear girl! The only way from here is UP!!