Phase One:  you actually believe that biodad just "needs help" parenting and that SKIDS AND BM are the entire problem.

Phase Two: you are flabbergasted when all your efforts to "help" are spat upon.  You are told you are overstepping your bounds but in the same breath are expected to financially back your "bonus family."

Phase Three: You are now the ogre for having expectations of proper behaviour slightly more advanced than a common earthworm.  Welcome to eeeeeevvvvvviiiiillll SMville.   At this point you will be told that you "don't like my kids" and  "should try harder because you're the adult" (TM)

Phase Four: You decide to back off in which you are declared "uncaring" and "unhelpful" by biodad.  At this point you see one of the biggest causes of spoiled children....BIODAD!

Phase Five: After backing off, biodad is faced with having to parent his own child (clutches pearls).  The HORRORS!   Biodad will become exhausted and cranky having to deal with the monster(s) he and BM created.  He may continue ostriching... he may even (gasp) start setting miniscule specks of rules in which the skids will dramatically protest.

Phase Six:  CPS is called by the BM and accusations fly.  SM continues to be the common enemy of all.  At this point SM decides to go full on protection of one's sanity.  Bio dad will continue to do the one step forward two steps back backslide tango.  Perhaps even exclaiming that "he can't please everyone"(TM).  You may also hear shades of the one-big-happy-family model ,(TM) in the expression "I just want everyone to get along; is that too much to ask?"  And yes it is too much to ask especially when the BM is openly PASing out the skids and encouraging them to be absolutely rotten during visitation.