In the past I have always de-stemmed my fresh spinach leaves. But I am wondering, is that necessary? I'd like to prepare as-is.
In my experience, stems can be rather stringy even after cooking. Likely varies by time of year, age/size of leaves, soil type, cultivar etc. Best adivice is probably to check a few stems (raw, steamed, whatever) and see. I always cut stems off at the base of the leaf, and have yet to have a complaint about the stem bits within the leaves.