It's never easy being a parent. Hardest job in the world. I agree with the others, pick a time to sit down and talk to her in complete honesty, and yes, show her what you wrote here. But in the end, they are just words, and mean little to anyone if they are not followed up with actions.
I think, particularly following a setaration, kids fail to see their parents are in a bad way possibly, but then again I think parents often fail to see the kids are also feeling it badly.
No person, thing friend, nothing takes priority over children IMO. I also think when life gets to the stage where a parent is not spending enough quality times with a child, life needs to be looked at ruthlessly, and if need be, some things need to be canned.
I guess what I'm trying to say is that once the kids have left home, we have a lifetime of being able to do what we want, when we want. But we can NEVER take back those years with our children! Maybe consider simplifying your life abit. Look at what you can wipe to spend more time with her, or change schedules so it works better for both yourself and your daughter.
I have learnt that a lot of children think we are invincible, and when we sit down with them and throw evereything on the tabel in TOTAL HONESTY, they realise we are feeling the exact same things they are - I have found that helps dramatically when having relationship issues with your children.
All the best. Oh, and a big hug for you, because realising this needs attention is the first biggest step IMHO.