How liminal space theory and a dash of Renaissance wisdom can help when your life is between acts. — Throbbing with life 24/7, Piazza Santo Spirito, in Florence’s achingly cool Oltrarno district, has been a meeting place since medieval times. Edged with gasp-inducing 15th and 16th-century buildings (including Palazzo Guadagni, on whose chilly candlelit balcony my chaplain husband, wearing army dress uniform, proposed) it is dominated by a Renaissance…