Usually, Pisces, but their opposite, Virgo can be equally compatible if there's enough water in their birth chart.
Pisces
It depends on the individual birth charts. Virgos can be too much alike, and Scorpios can be more challenging.
Aries - Libra Taurus - Scorpio Gemini - Sagittarius Cancer - Capricorn Leo - Aquarius Virgo - Pisces
You will have to give your date of birth, place of birth and your time of birth to an astrologer for them to interpret your birth chart or give you an astrological forecast. Your Sun is in Aquarius; Moon is in Aries; Mercury in Pisces; Venus in Capricorn; Mars Pisces; Jupiter in Virgo, Saturn in Aries; Uranus in Virgo; Neptune in Scorpio and Pluto in Virgo.
Scorpio!
You'll need to check the birth charts.
* If you are believing in birth signs and Horoscopes then you are being unfair to your boyfriend. There is no indication that Virgo and Pisces cannot get along and if you continue with these suspicions on Birth Signs alone you will end up the loser. If you feel he is cheating on you it has nothing to do with being a Pisces and you a Virgo. Some men and woman of any Birth Sign can cheat on one another.
The Sun sign is Aries, Moon is Leo or Virgo depending on the time of birth, Mercury is in Pisces, Venus is in Aries, Mars is in Aries, Jupiter is in Gemini, Saturn is in Scorpio, Uranus is in Aries, Neptune is in Pisces and Pluto is in Capricorn.
The mutable signs are considered to be the most changeable: Gemini, Virgo, Sagittarius and Pisces.
If you're referring to Arianna Grande her Sun sign is Cancer, Moon sign Virgo or Libra depending on her time of birth, Mercury sign Cancer, Venus sign Taurus, Mars sign Virgo, Jupiter sign Libra, Saturn sign Aquarius or Pisces depending on her time of birth, Uranus sign Capricorn, Neptune sign Capricorn, Pluto sign Scorpio.
The zodiac star sign for September 5 is Virgo (August 24 - September 23).
Ian Virgo's birth name is Ian Frederick Virgo.
You would have to use a natal chart software and plug in the exact time, date and location you were born in order to know your "rising sign". The rising sign is the sign being revealed at 0 degrees (first house) on the eastern horizon at the time of birth. If your rising sign is in Cancer, Pisces or Scorpio, it is in water.