Thanks for writing to Just Answer.
You seem to have a fairly high degree of self-awareness, as you note that you know at times you're rationalizing, but you are indulging in some very risky behavior.
The situation of sleeping with a man without protection when you don't allow your husband the same freedom with you suggests that you may have some unacknowledged rage against your husband. This can happen when a present situation reminds us of something from earlier in our life.
For example, while you make a good living and intellectually don't mind supporting him and his art, this may remind you ---subconsciously---of a time earlier in your life, usually childhood, when someone who was supposed to take care of you didn't, and you had to "make do" with what you could do for yourself.
You have, in a way, developed a relationship with your husband that keeps him in the role of adolescent. You pay for what he needs, like a parent. You also don't allow him to come inside you--which is the way teenagers try to deal with the pregnancy issue. Why not use a form of birth control so that you can have adult sex with him? (Since you took the morning-after pill, it would seem that you don't have any religious or other restrictions against birth control.)
You have him under very tight control in two main areas of life--money & sex--and while you may on one hand enjoy the control, it sounds as if it also led to you feeling disdain for your husband for needing/allowing you to have all the control.
I think it would be a great idea for you to find a therapist to work on these issues with. The fact that your behavior is becoming more risky (no protection) says that these issues are starting to affect your life and need attention. This goes deeper than anything that a correspondence online would be able to solve.
The most sensible things to do is are:
1. Get a therapist
2. Stop sleeping with other men until you have resolved the issues that I mentioned earlier.
3. Tell your husband he has to contribute to the household. Very few artists can live on their art alone, and it is not unreasonable to expect him to work, at least part-time.
4. Get on a form of birth control so you don't have to make your husband pull out.
5. Don't put yourself in situations where you can end up having illicit sex --pregnancy is not the only danger--how will you explain to your husband if you get an STD?
6. The time to think about whether to leave or not is after you have dealt with the issues in your marriage--otherwise, they will more than likely repeat themselves in your next relationship in one form or another.
I wish you all the best as you work through these issues in your marriage,