If he already has a woman in his life I guess he doesn't need intimate time with you, amirite?

He can't have it both ways.  Either you're the woman in his life or you're not.

Run if you can. Disengage if you cant. 

He has to pick her up or get it change.  You will always be wrong.  Both your DH and BM will give you a hard time.  Stops the picks ups.  

Are you 2 married currently?

This is a huge red flag if you are not married. Because he is not stopping her behavior. It has been brought to his attention by BM that these things are being done on purpose, and he is not consistently shooting it down. Half the time doesnt work, it must be ALL the time. Thusly you should conclude that he is enjoying all this attention and adulation, and you are preventing it, in the way as it were, and calling out its inappropriateness.

Guess what will probably happen if you were to break up? She will go on to ignore him. Game over, she wins. He will beg you to please come back, everything is different. Until you do, then its back to her doing this.

HE needs to shut it down. When SD13 gets too clingy and tries to "bump her way" in between us, he will shrug her out. If she interrupts, he will ignore and keep talking.

When she used to try to kiss him like she did as a young toddler, he stopped her (at 8). We have 3 couches, and he prefers by me. She doesnt get in the middle of anything and actually prefers talking to me as the woman of the house. These games must stop. SO needs to stop them.

Ugh. Sounds exactly like my SD12. She literally just left so I’ve fresh off of 4 solid hours of this mother freaking bull crap. DH was even gone for about an hour and SD acted normal and talked normal....then dh got back and she went back into a mental health patient mode.

I actually like her when dh is not here but I hate her guts when he is. Thank god my dh is so over her Behavior that he has been ignoring her.

if I were you....tell him. But also ignore her.....acting like they don’t exist really helps.

Skid25 is bad enough. 
I don't think I could handle it however I would not be doing anything for her, like picking her up unless my DH got on the same page and disciplined and shut that behavior down. 

Just ignore her and him. When she gets all stupid and giggly walk away. Tell DH that her behaviour reminds you of the boy crazy girls in elementary school and is rather creepy.

Doesn't he want to raise a well adjusted independent girl who can take care of an apartment and know how to call a plumber or electrician or organise car repairs without needing a man to do it for her? How can he endorse her baby behaviour? Women can still adore their fathers and lead susccessful lives without being up their fathers behind all the time.

When she does her little act I would lower my head just a little and have a smirk on her face. Wearing glasses and looking over the top of them works even better. Then make a 'humph' noise with the smirk. Turn around and walk away. She will get the message. Show her she is not equipped for the Big Girl World yet and you have her all sorted out.

ETA: As for the school pick up. Just tell her as you are not her mother you do not need to pick her up. Would she like to walk home? No? Then she can say Thank you and Hello and be polite, Or you may just stop the car and turn it off until she says anything.