Thank you HKK for the revised chart, it's much better. In the future, try to insert also the South Moon's Node, which is helpful and when it isn't inserted can slip by.
As Conspiracy Theorist wrote, you two are separating.
But what are you separating from? A square. So the relationship in reality was not an easy one.
The fact that Saturn is in its own sign and in the 7th representing him shows he stood on his own in the relationship. He wasn't really with you. Retrograde he was running away from you, not walking, to be out of the relationship.
Saturn had been on Pluto which represents deep forces, and it is co-ruler of his 12 house showing he had subconscious reasons for being in the relationship, perhaps didn't even understand them himself, but was guided by instinct. Saturn and Capricorn are not expansive and emotional, but calculating and tend to take advantage of a situation. His "backstabbing" might have been part of this, if he was bragging to others it would give his status a lift, in his eyes. (Don't assume the others necessarily agreed with him, they might have internally criticised his betrayal.)
He went towards a partile semi-sextile with Jupiter in his 12th, so he was in fact able to get some relief and did work out some of whatever his issue was.
South node on Saturn shows he had some kind of karmic debt from the past to pay off, he was there but it was not easy for him. (See it is important to see the South node position).
But Pluto in your 7th shows a controlled situation, a purging, and you as moon in Aries of the individual ego rebelled against this. Moon is not strong in Aries so you were in a weak position, your energy not expressing itself well with him.
South node in your 7th also indicates that it was a weak contact for you, you were giving, being drained.
At this point, where to go? You won't be getting together again, as we saw earlier, but will the lessons from this relationship help you with future ones? Look towards Chiron of knowledge and lessons, and it is sitting on the cusp of your 11th house of future and wishes. Think back on the relationship only to gleam this lesson, then leave it behind you and move on in a stronger state of being.