I have a 19yr old son that hates my husband. My husband is not his father but has been in his life for 13yrs.

My husband and I have been together for 13yrs. My oldest son hates him. He does spiteful things like burning the tip of an inkpen and then putting the ink all over my husband while he was asleep. My husband and my sons father have a great relationship. He is constantly telling me that I let my son get over on me and that my son always seems to find a way to make me side with him.