I understand your situation completely, as I just married my husband (19 years my senior) in November 08 and he had a 16 year old son and 20 year old daughter.... We are definitely having some issues, but nothing we cant handle... Step son (16) is a normal pain in the butt, always wanting something yet not wanting to do anything to get it (but [censored] and moan).... and Step daughter (20) just moved back in recently, and is not trying one bit to leave the house, as she has got it made.... I honestly think her father is going to blow up pretty soon though, and tell her she has a month to get out, since she can't do anything around the house, is alwyas gone or wanting to use our vehicle, can't pay the $200 rent (if so, not on time) and is constantly over drawing her bank account on her pay days!!!!!!
Step daughter and I get along fine, she is a sweet girl, sometimes to sweet especially to her rude, and lazy brother.... (she gets that from her father). Now my step son and I butt heads alot of course.... as he is just rude and lazy, and never has anything nice to say unless he wants something.... We're currently dealing with his school work and grades, as I can see every assignment and tardy/absence on-line from his school. So he has been grounded alot lately... as I dont really think that his Dad did much of that until I came into the picture.... (the kids were very spoiled until i moved in) I told him they need to learn to be responsable for themselves, what are they going to do when they are out in the world.... Lord who knows right now, they cant even fry an egg..... but i honestly hope they both leave soon, as I would love to have a child of my own one day, and sometimes when i get home I just want to run to my room because i dont even want to deal with them or hear their voices....