Jamie Webb launched his campaign of harassment last year.
Between August 10 and September 16, 2021, the 52-year-old, of St Andrews Road, Southsea, sent texts to the pair and visited the mother’s home, uninvited.
Webb pleaded guilty to harassment on during a previous hearing on December 15.
His case was adjourned for pre-sentencing reports.
Webb is due to be sentenced at Portsmouth Magistrates’ Court tomorrow afternoon.