By the sound of the posting there is a huge resource here so I am writing my story of being a step-parent and hope to get some useful tips and encouragement.

I have been with my current partner for 1½ yrs. His son G who is now 4 has only been with us half time and the custody is not settled yet. For the first year we had G for 2 weeks and his mother then had him for 2 weeks. She is a very unstable person and very volatile. Often she would call asking us to take G because of various excuses. In January we moved to a different city and their case was heard before a judge who granted a 6 month interim arrangement for 4 months/4 months custody and at the end of the 6 months they were to come up with a more long-term arrangement. Just before the time was up the ex-wife decided to get a new lawyer so things have been hung up. She has informed us that she wants full custody. She has had 6 dif jobs since they split up and always financial problems and now G is starting to show behavioural problems with her. He is outgoing and respectful and alot of fun and listens and is polite with us. With her he has poor nutrition and is sick most of the time and he is disobidient and often is sad when we talk to him on the phone. This past May we have a new son A and G loves him so much and now always wants to talk to him on the phone.
This is so heart wrenching for me because I have no say in G's life. I love him as my own son and he even started calling me mommy (by his own choice) during the 4 months he was with us). The moment he got home with her, after she had a 'discussion' with him is now calling me K again. She is jealous and vindictive and selfish and is impossible to talk to.
Well, that's the abridged version. Tips welcome.
-K.