As you point out, the late degree on ascendent would indicate that action has already been taken on this issue. And in fact, apparently he has already decided to remain friends with his ex, based on what you wrote.
In addition, note the north moon's node is also there on the ascendent.
Remember to insert the south node when you do a chart, and here you would see it is sitting on the 7th cusp.
The south node is karma, it is past lives. His relationship with his ex has a karmic aspect to it.
With ascendent on north node, you represent the future, but he still has to work out what has been left suspended from the past with her. And it is important for both of them that they work it out.
You are mercury, in the exaltation of Jupiter and terms of Jupiter, showing how much you care for him. You are in the first house, thinking about your situation, and also retrograde, in a phase of rethinking the situation, and in contact with Venus, who rules your 12th. So a lot of subconscious work going on inside you.
Mercury will then retrograde to a square with mars, anger, in your house of wishes and hopes. Cancer mercury clings to the past, while Aries mars is aggressive and egotistical, watching out for itself. So you are undecided which path to follow. And this creates a conflict and a big dilemma for you.
What is your partner up to, aside from the karmic contact with south node?
He is Jupiter and he also is retrograde. In Capricorn, retrograde, and in the house of mars, he has no strength, he is between a rock and a hard place, as they say. He will conjunct Pluto, the planet that transforms by first destroying, and then rebuilding, energy that digs to get to the bottom of things. It rules his 12th house, so he too has a lot of subconscious mulling going on, he is beginning to withdraw into himself, being overpowered by the force of Pluto.
Moon, the question, just separated from the opposition with sun, which is the difference you two had about this situation.
I prefer not to use the secondary significators, normally the primary ones are sufficient, but in this case, given that the sun/moon opposition took place in the ascendent/descendent, and the moon is your secondary significator, while sun is his secondary, the positions of these two planets are important. You are in his house, he is in yours.
In addition, they are each in the other's natural sign. This gives the idea that in spite of the separating opposition, you two are together and a couple.
Moon now moves towards him, Jupiter. You want to remain with him. Jupiter has no reference or contact with mercury. However, the moon separating from mercury, and sun, and now approaching the conjunction with Jupiter gives hope that you will be able to maintain the relationship with him.
So, what about his ex?
We can't assign her to his 7th, because that is where you are. If we assign her to his 11th, as a friend, she would be mercury, who is already you the querent.
She could be his 5th of love affairs, and she would be Neptune and Jupiter. Jupiter is already assigned to him, so she is Neptune. Which would indicate someone who is stealthily sneaking into the picture. Jupiter had been in aspect with Neptune, but has moved on. Significantly, the cusp of his 5th (the radical 11th) is at the last degree of the sign, so about to move on.
Moon will sextile her, Neptune, but then move on to the conjunction with Jupiter.
So, it looks as though he will finish whatever unresolved issues he has suspended with her, which he himself might not be able to identify, and then let go of her.
In any case, remember, the past is the past, treasure it but don't build your foundations on it. Look forward, consider you and your situation, and what works best for you. Try to be patient, the dice have been cast here, you have only to wait and see what number comes up.
