The 26-year-old Pakistani woman, SB, was initially refused entry to the flat by her husband, KR, 38, but on entering discovered an Indonesian woman hiding on the balcony with only a small towel covering her lower half, the report said.
The husband and his 27-year-old lover, NB, were charged with having consensual sex out of wedlock.
The Indonesian woman, who works as a maid, was additionally charged with absconding from her sponsor.
The pregnant woman told prosecutors she had left her husband as he had quit his job and was regularly asking her for money. She has a seven-month-old baby from her relationship with KR.
The wife grew suspicious and went to meet her husband, after he had earlier refused entry to her brother, who went to the flat to collect some documents.
The husband and the maid confessed they had met two days before the incident.
NB said she had absconded from her sponsor about three months before and KR promised her a job with a good salary.
According to the report, KR pleaded guilty at the Court of Misdemeanours, but NB was not present.