Enrique Simonet Lombardo (February 2, 1866–April 20, 1927) was a Spanish painter.
The full title of the painting is Anatomía del Corazón; ¡Y Tenía Corazón!; La Autopsia (Anatomy of the Heart; And She Had a Heart!; Autopsy). Simonet painted it in Rome in 1890. Signature, location, and date are in the bottom left corner: E. Simonet / Roma 90.
Wow! She really did love me with all her heart.

Enrique Simonet — Detail from La Autopsia (1890). Public domain.