Do hard Pluto/Saturn/Mars/ Nessus aspects always depict some kind of abuse in synastry? Particularly if the aspects are repeated or reinforced in some way in synastry and composite?
Have you been in an abusive relationship or know someone who has? Have you seen any of the aspects above emphasized in the synastry/composite?
How would you describe the feelings in the beginning if the relationship and how did the abuse play out? Did it play out typically or was it subtle? Did the houses afflicted in each persons chart describe the abuse?
This is an interesting topic, one that puzzles me as well. When I look at the synastry between me and the most abusive people in my life, there are many conjunctions and trines, but few oppositions. I sometimes think astrology plays out backwards in my life. The people I should have better synastry with, are the ones I have the most trouble getting along with. The one's I'm not supposed to have it with, the relationships are better. I don't know what to think 
Same here Kab, it does seem that way sometimes... Astrology can be puzzling... Because a hard aspect for one person in synastry is beneficial to the next person....
It's so deep and so hard to interpret certain aspects between people. It takes a long time of looking at the two charts individually and then together... It takes a very high level of intuition and insight...its very confusing sometimes because once you think you have something pegged, you gain a new insight.
It's sometimes best, I think, to go with your feelings than stress yourself out over synastry...
There are certain markers that do cause trouble MOST of the time.. but it all depends on so many factors.
These were present in each of my nightmare physically and emotionally abusive relationships:
So, Mars/Neptune natally and/or in synastry. (Cos, you need someone who will consent to be your punching bag, in the first place.)
Venus/Pluto natally and/or in synastry (double trouble for me again.)
Annnnd Mars/Saturn and/or Saturn/Sun... IN the chart of the abuser, or in synastry.
Aside from these three, which I believe are a perfect cocktail, are the following:
My ex hubs had Mars/Saturn tightly conjunct, squaring his Sun/Venus/Jupiter/Merc. He also had Pluto sq Moon.
My ex boyfriend and I had Saturn opp Sun (He was Saturn, I was Sun), His Sun/Merc in Virgo in the 3rd square my Merc Chiron in Gem in the 12H (super, extremely verbally abusive). His Mars square my Moon/Jup, and his Venus conj Pluto in Scorp opp my Venus. My Mars opp his Neptune.
Sometimes I think it's just the Pisces in my, not wanting to deal with things. I am strong and often hard headed, or so I've been told, but always, I am my own person. I won't let anyone take that away from me.
l find Mars/Moon to be really difficult in synastry.
l have a friend and somehow he keeps on making me angry, l find him pushy and irritating. l say NO he doesn't hear it!
l can feel angry for an entire day...! l don't have this with anyone else.
so l thought let me have a real good look at our synastry and there it was: his taurus mars is opposing my Moon. 
argh!
l read about it and it was exactly how l felt around him.
i think it's not just the synastry l think he has some disorder.. he has problems with many people and has a history in stalking his women friends, is socially isolated and finds it difficult to relate to people.
l accepted him as he was.
l also felt sorry for him so l kept the contact going but at this point l had enough ((((
so yes mars/moon not a fine combo!!