Having worked with kids for years, too many of who came from blended families, the highest praise I have ever heard about a step-parent was 'he/she is ok.' Ok? Yes, ok. That's it.
Kids do not want a step-parent. They want their family intact. Obviously, there are reasons why families simply cannot remain together. However, when considering re-marrying, take time to really see who your new partner is. If you have daughters and you are introducing a man into the family, who is not related to them, how responsible is he? Does he have boundaries? Is he too interested in them or not interested enough? If you are a man, with children, really evaluate the qualities of the woman to whom you will expose your kids. Is she seductive (which is appealing as an adult) around teen boys; is her dress appropriate to model for your young daughters? How is her relationship with her ex and will it interfere with your lives?
The traditional lament is: "But I have a right to be happy. I have a right to a fresh start; a new life." You do, but happy ever after is in novels. After the thrill of the engagement, the glamorous second wedding, the honeymoon, you settle into a real life, with problems. If you had a crystal ball, and could imagine worst case scenario for this marriage, would you be in such a rush? Look in the newspaper at the damage kids can bring to a relationship. In addition, decide if there are red flags you are ignoring: gambling; drinking; drug use; anger issues, etc. THEY DO NOT GO AWAY.
Troubled children are a weight on the relationship of the two people who are his/her parents. A step-parent is not going to be able to balance heart and head. There will be lots of fighting about how to help the troubled teen; the child's interaction with the kids of the new step-parent, etc.
Why not date and just keep the families separate until such times as the teen hopefully outgrows the problem, or moves out and onto a life of his/her own?