L.,
I GET IT!!!
I absolutely understand where you are coming from. Like you, I work Full-Time, and only get weekends with my Daughter. Other than that, she's in After-School Care, or Summer Camp while I am at work.
Although my Divorce made me feel a certain way about my Ex, we Co-Parent our Daughter very well. He travels for a living, and pretty much does the 6 months on, 6 off thing. Just like your situation, when he has his Girlfriend, or Family over, he pretty much dumps our Daughter off on the Female. My Daughter is always sad when she comes home, because she says "Daddy doesn't make time for me."
Now, the Step Mom thing.....I can see where your sad feelings come from. Your Daughter's world was turned upside down with the Divorce, your Days and Nights with her are now limited, and in comes someone new (that she HAS to spend most of her time with) at her Father's home.
ALL of this is strange to her, and somewhat unfair, but unfortunately, it is what it is. It IS nice that you have developed a good relationship with the new Stepmother, but your Ex HAS to start making at LEAST an effort to try to free up some time for his Daughter.
I know how it feels when she's not with you at home.The overwhelming Guilt, because she has to be shuffled back and forth.....all of it really sucks!
I will tell you this....my Ex recently sent me a "HELP ME" text message. He said he feels like he's losing his Daughter. I have told him for MONTHS to make more time for her, and he wouldn't listen.
Your Ex doesn't want this to happen......
I hope he wakes up, before it's too late!!
Hang in there.....do what I do. Make sure ALL the housework and errands are run before your Daughter comes back to you, then spend all of the time you can with her.
Oh, and another thing.....IGNORE all of the people in here who feel like they need to try and BULLY you with their insensitive comments!! There is a RIGHT and a WRONG WAY to give "Constructive Criticism." Some people have pretty PATHETIC lives themselves, and try to come here to tear others down. Just had to put a poster in check yesterday about that! LOL!!
Stay Strong my Dear!!