The wife of slay-suicide cop Sean Armstead was spotted outside their upstate home Tuesday — the first time she has been publicly seen since her husband killed her young alleged lover and then himself over the weekend.

Alexandra Vanderheyden, 35, appeared disheveled as she lugged what appeared to be a blanket and a blue garbage bag outside the Port Jervis home.

She had allegedly been with her 20-year-old boyfriend Edward Wilkins at a hotel Sunday before her jealous NYPD officer husband tracked them down and fatally shot him. The off-duty cop then turned the gun on himself.

Armstead, a veteran Bronx police officer, had called in sick from his midnight shift and trailed the pair to a La Quinta Inn in upstate Wallkill.

Sources said Wilkins met Vanderheyden when he took a job as a dog walker at the older woman’s dog-grooming business.