Hi, I'd like to help you with your question.
It is very good that you recognize that you are in an unhealthy relationship with the woman you met on line. That is an important part of weaning you away from this relationship.
Although it does sound like the woman is very nice, there are several red flags you mentioned. One, you did not mention if this relationship is still restricted to on line or if you have met this woman in person. Relationships on line are quite risky and often involve one party seeking financial help in some manner. Even if you have met your friend in person, it sounds like she is taking advantage of you. This is not a trait of someone you want to spend your life with.
Two, do you know if your friend is being honest with you about where the money is going? If she has a son with a drug abuse history, part of your money could be going to him.
Three, has your friend reciprocated in any way? It sounds like your relationship is a one way street. Has she made any effort to support herself? Find a cheaper place to live? Do her children work at all? If the answers are no, then she is most likely using you.
Four, you took on the new relationship before you had time to recover from the break up of your marriage. Most likely, you are feeling alone and vulnerable. That is very normal. For that reason, it is often a good idea to take a break between relationships so you have time to reflect and heal from a break up.
When you start removing yourself from the relationship with your friend, start slowly. Begin giving her less money. Start telling her that you feel you need time to recover from your divorce. Let her know you are taking some "me" time. All through this, reinforce that it is not her you are leaving, but you that needs time. Tell her you feel you are not ready for a serious relationship right now and that it is not fair to her that you continue. Then keep withdrawing financial support. This gives her ample warning to find another means of support so she can stand on her own. By refraining from making this her issue and by blaming yourself, you can let her go gently. And whenever she looks back at the relationship, she will see it as your issues and not her that was the cause. That is the gentlest way to end it.
I hope this has helped you,