Through astrology we can predict and understand breakups.
Most often a breakup is caused by a transit of an outer planet to one of the significators of love in your birthchart.

Most vulnerable in the natal chart :
• Venus = Love
• 7th ruler = Relationship
• 7th house & planets in 7 = Relationship
• Moon = Feelings, heart, female figure
• Sun = Expression, male figure

Often it’s the outer transits that trigger a longterm period of challenge. Slow but surely tension may build up.
Outer transits to either one of the planets above, can strengthen of break a relationship.
If something wasn’t going well between you for a while and Pluto hits you with that square to your natal Venus or 7th ruler, it opens the opportunity to clean out the crap and break up. Hardships can be binding or a dealbreaker. Much depends on how you both really feel in the relationship.

Eventually it’s transits from inner planets that will act as a trigger, such as a full or new moon, especially when it’s in aspect to one of the significators of your 7th house. Let’s say there is square from saturn in aquarius to your venus in scorpio, it’s a full or new moon in aquarius or scorpio that could manifest an event. The same applies if this lunar event is in aspect to either venus or the 7th house.

Saturn

= Restriction, testing the structure of relationships, obstacles, frustrations, depression
Most often a hard Saturn transit relates to a low self-esteem and being more detached than usual. This could result in emotional distance between two people, in which the other partner doesn’t feel much connected to you or the relationship. Saturn is known for the cause of breakups, in this case it’s either you, for not seeing what you actually have for example (Saturn square Venus), but this could also result in the partner breaking up due to longterm emotional distance between you both.

Transit :
• Saturn square, opposite Venus
• Saturn square, opposite 7th ruler
• In 7th house
• Saturn square, opposite, conjunct Moon
• In a hard aspect to planets in 7

Progressions :
• Saturn square, opposite Venus
• Saturn square, opposite 7th ruler
• Venus changing sign

Uranus

= Restlessness, breaking free, liberation, need for new things
Hard Uranus transits are linked to desperately seeking new experiences and pleasures.
Uranus opposite Venus could result in changing values onto love and relationships, either in you or the partner. Cheating is linked to this transit due to a restless need for new things to the point of almost blindly jumping into something new. Uranus is unstable and unpredictable.

Transit :
• Uranus square, opposite, conjunct Venus
• Uranus square, opposite, conjunct 7th ruler
• in 1st or 7th house
• Uranus square, opposite Mars or Sun
• In a hard aspect to planets in 7

Progressions :
• Uranus square, opposite Venus
• Uranus square, opposite 7th ruler
• in 7th house

Neptune

= Illusions, delusions, cheating, self-undoing, sacrifice, secrets, lies
A hard Neptune transit is linked to cheating. It’s either you who ends up cheating on your partner because you’ve met someone new who seems to be so perfect, but with a hard Neptune aspect you don’t see things clearly.

Transit :
• Neptune square, opposite, conjunct Venus
• Neptune square, opposite, conjunct 7th ruler
• in 7th house
• Neptune square, opposite Mercury
• Neptune square, opposite, conjunct Lilith
•In hard aspect to planets in 7

Progressions :
• Neptune square, opposite Sun
• Neptune square, opposite Venus
• Neptune square, opposite 7th ruler

Pluto

= Transformation, depth, intimacy, symbolic death/rebirth
Hard aspects from Pluto are linked to breakup, however often they show a temporary breakup ; symbolic death & rebirth. If it results in a permanent breakup, it’s often a painful one, but it will bring you something new. Pluto will always give something in return, but that what’s not functioning and aligned with you, has to go and this loss can be a wild ride.

Transits :
• Pluto square, opposite, conjunct Venus
• Pluto square, opposite, conjunct 7th ruler
• Pluto square, opposite, conjunct ASC
• In hard aspect to planets in 7
• Pluto square, opposite, conjunct Moon

Solar Return 

• Uranus in 7th
• Uranus square Jupiter
• Uranus square, opposite Venus or 7th ruler
• Uranus square Pluto (Sudden painful breakup)
• Saturn in 7th
• Saturn square, opposite Venus or 7th ruler
• Neptune square, opposite Venus or 7th (Being cheated on)
• Neptune in 7th (Being cheated on)
• Venus square Pluto (Painful breakup)
• Venus Retrograde (Multiple partners possible in the same solar year)
• Venus square Jupiter
• Moon in Scorpio (Intense emotions)
• Moon opposite Saturn (Depression)
• Moon in 7th (fluctuations)
• Chiron in 7th
• 7th ruler square, opposite Pluto
• 7th ruler square, opposite Lilith (Being cheated on)
• 7th ruler square, opposite Sun
• 7th ruler square, opposite 12th ruler (Being cheated on)
• 7th ruler in Aquarius
• Lilith square, conjunct Neptune (Being cheated on)
• Aquarius DSC (Multiple partners possible in same solar year)

Air sign DSC :
I have noticed that whenever the DSC in a solar return chart falls into an air sign, that there seems to be a possibility of having multiple relationships within the same solar year. A relationship breaking up and another one beginning for example. Or an overlapping of two relationships such as being in a relationship but meeting someone else, which eventually results in the breakup of the current one and the start of a new one.
I have noticed that when the DSC falls into the sign of Aquarius it shows the possibility of a current relationship breaking and a new relationship starting, but of longterm due to Aquarius being a fixed sign.

Pisces DSC :
Pisces rules over the 12th house and Neptune, therefore illusions and secrets are related to the 7th house when it falls into the sign of Pisces. Ofcourse there should be more indications inorder to foresee a breakup which results out of being cheated on.

N.B :
Some of the aspects listed above could possibly show up in charts of a year in which there is tension within a relationship. One of which i have seen :
Venus square Pluto (separating)
Pluto square Uranus (applying)
Mercury square Neptune (Lying)
Moon opposite Neptune (Delusional)
The ASC was libra. This was the solar return chart for the first year of a new relationship which evetually lasted for years, however the individual dealt with heartache from a previous relationship which is shown by the Moon and the Venus. Be cautious in your analysis and always reflect back to reality before concluding a breakup is ahead.
These difficult aspects could also show tensions and frictions, but if there is enough love and understanding, you can work through these aspects as a couple.

Lunar Return

• Venus opposite Neptune (Cheated on)
• Venus opposite Saturn
• Venus square Uranus
• Venus opposite Pluto (Painful breakup)
• Moon conjunct Saturn (Depression)
• Uranus opposite Mars
• Uranus square Pluto (Sudden painful breakup)
• Uranus in 7th
• 7th ruler conjunct Uranus
• 7th ruler in 12th (Being cheated on)
• Mars square Uranus
• Lilith in 12th (Being cheated on)

The indications in the Lunar return chart are very similar to those in the Solar return.
• More research is needed

Transits to Composite chart

A very accurate method to predict breakup as it is the chart of the relationship itself.

• T Uranus square, opposite, conjunct Venus
• T Jupiter Square, conjunct Uranus
• T Saturn square, conjunct, opposite Venus

These transits also apply to the Composite Sun, Moon or ASC & ruler

Is it permanent?

If a breakup occurred during the classic Saturn square Natal Venus or 7th ruler, than yes.
However if Saturn is retrograde and it’s the first time it aspects your love significator, than it might not be the end, yet.
Retrograde planets give a clue to a breakup being permanent or not.
Usually during a retrograde aspect, the breakup will become permanent if it’s the last time the planet aspects your love significator.