Step son stole from me and destroyed my property- should I be catering to him?? ...?

Oh hell NO! And I am sorry but you also need to find a new fiance. His son's lack of respect for you has been learned! I would suspect from his father, YOUR fiance! You are in for a hard life girl if you choose to continue this relationship and ESPECIALLY if you have a child with him. Sorry to be so blunt but it's the truth! Good luck.