His Sun and Mars in your 8th house might give you a visceral reaction to him.Your Mars is conjunct his Saturn and also squares his Mars.
While I have seen that Mars-Saturn aspects aren`t as bad as they are suggested to be, it seems that it is not a good idea to have another planet challenging this combo, especially not Mars (uranus, SAturn or Pluto).
While probably in the beginning there might be a strong pull, it can lead into something like "combat-embrace", people who argue all the time and still can`t disentangle.
He has the Mars-Saturn-challenge natally, an inbuilt stop-and-go mechanism, but I don`t know how well you could deal with it, as you donīt have a natal Mars-Saturn aspect. However your Venus is conjunct Saturn natally, so this might actually be a point of complimentarity, resonance and magnetism. How healthy this is, I donīt know.
the ruler of your 7th house is unaspected by his planets, which is not really that favourable for a committed relationship.
The ruler of your 5th house, Venus, is conjunct his Neptune, which is a "glamour-aspect", might feel like magical romantic bliss to you (though could also leave you puzzled and confused).
Unfortunately he has Neptune squared to Mercury; could lead to some elusive confusing behaviour on his part (or in the real worst case scenario this can be a combination of the "deceiver", but of course it doesn`t have to be like this. Maybe he is just having an imaginative mind).
The Sun-Jupiter-conjunction is a really nice one, bringing supportive feelings and friendship.
However there are no strong aspects to your angles.
There are also no Sun/Sun, Moon/Moon, Sun/Moon-aspects.
his Sun is trine your Venus-Uranus(-Saturn)-conjunction though, and falls into your 8th house, which could be a point of attraction on your side.
His Venus trines your Neptune - so there is a DW, which gives a lot of romantic magnetism; only problem is Venus/Neptune is not really of this world.
I also would have preferred if his Venus was aspected harmoniously by your personal planets or angles, indicating he is drawn to YOU as a person (and not necessarily be under a "spell", as the outer planets often produce).
his Mars trines your Sun, so ther emight be some physical vibe there, harmoniously energetic and dynamic.
Your Venus-Saturn-Uranus is on his SN, which speaks of a karmic connection. You come from his past, so to speak. With Venus there, probably a past life relationship, whose magnetism carries over (but usually isn`t enough to carry through a whole life on its own).
Saturn-SN is glue that is very hard to break, though people usually will try it, as it often feels too "heavy".
His Neptune squares your nodal axis, and this is the one aspect I am really wary of. Just because when I investigated successful vs failed relationships (I mean like tragically failed), I invariably would find one person`s Neptune squaring the other perosn`s nodal axis or being on the SN, while this did not appear in even one single of the lasting relationships.
I donīt think it spells doom, as no aspect evwer does, but I would keep an eye on how grounded the relationship really is, a reality check now and then will be needed and absolute honesty with each other.
(which might not be easy for him with his own Neptune on his SN squaring Mercury, it is definitely some kind of "lesson" to him).
EDIT:
Maybe have a look at the progressed charts as well.