Without seeing any of your samples or the fabric or the furniture or the floor or your accessories, I can only suggest Sherwin-Williams SW 6218 TRADEWIND which is a soft greyed blue that would give a 'sky' effect and would contrast nicely with white trim (SW 7002 DOWNY would be pretty for that). Pick up the fabric's blue-ish green in artwork or the curtain fabric (not a solid, but an airy print).

I find this barely there blue soooo serene. The photo link identifies it as Dolphin by Martha Stewart.