2 jobs.. one full time one per diem. Need Advice

I am a RN, and work 2 jobs, one is full time (at a pediatric hospital, I work 7/10 hour shifts a pay period, plus have to be on-call every 6 weeks on the weekend), the other job is a per diem job (at a psych hospital, I am supposed to work 2 12hour shifts a month, but its been hard lately b/c I have been putting in lots of time at my full time job).

I really want to resign from the per diem job, just because I don't enjoy working there, I am not learning anything new, I don't always feel safe there (patient population, and staffing is not that great).

I can always pick up more on-call shifts on the weekends if I need more $$, plus I am planning on taking a certified pediatric nurse exam in the fall, since I have at this same hospital for 3 years, I am trying to get specialized..

The only issue is that my husband does not want me to resign from the per diem job. He says that it will look good on my resume, and that I hardly ever work there (they have been pushing me to do more, and I have been able to do a couple half shifts, but now they are telling me that I can't do that, that I have to work the full 12 hours).

I just am trying to find away for him to see my viewpoint. I think all he is seeing is $$ and Resume building..

I mean, I have 6 years of prior psych hospital experience before I became a nurse and if I ever want to go back into psych, I know I could. I just really want to focus on peds now, especially since I am going to take a certification exam..

I hope this isn't too confusing.. just trying to get my thoughts out and try and find some advice.. Thanks for reading..

Also, as far as resigning, any tips on how to write a good resignation letter, that would allow for a possible to return to the psych hospital or the general hospital that affilated with it??

Any help/advice would be great.. Thanks all!!
I think you already know your answer about what to do about the PRN job. As for the resignation letter, the shorter the better. Dear ManagerThis letter is to inform you of my resignation, last day worked to be ______. I appreciate the opportunity to have worked at ____.Sincerelylakerette01Make sure one copy goes to your manager and one copy goes to HR