The widow is love's survivor — the one the vow's 'until death' delivered to the far side of. It names the state of outliving: the half of the pair remaining, the bed's empty side, the grief that is love with nowhere to go.
Positive Resonance
Love outlasting its object, the survivor's slow rebuilding
Shadow Aspect
The remaining half's ache, identity as the left-behind
Nuances
The empty side: absence in the shared bed
The widow's walk: watching for what does not return