Horse-widower
Horse owners, usually women, who give their horses the best of everything inevitably neglect their spouses and, like wives stuck at home while their husbands worship the golf course, the equestrian set has its own phenomenon, “the horse-widower”, who is left twiddling his thumbs while his wife grooms, mucks out and rides her horses morning, noon and night.
'His wife is always at the stables doing something with her horse, he's pretty much a horse-widower.