I saw this today in the synastry and the composite between me and this men, in whom I`am interested. Recently I had read many topics, forums, etc about the synastry aspects, because I want to be in clear with it. Especially with this guy, we share some very good aspects (I think so), but also we have some challenging aspects, too. So when I decided to see the composite to see the whole picture, I almost would cry. Moon square Saturn and Uranus (and Chiron)! Mars square Jupiter and Pluto. Jupiter opposition Pluto (these three form a T-Square). Sad!
In the synastry, like I mentioned already, we have love aspects for attraction, love, chemistry, sexuality etc, also for longevity (Some aspects with Saturn).
So! In my head pops up the question: if one couple have good compatibility in synastry chart - for long term relationship/marriage, but their composite chart have some challenging aspects - how this will work? Or vise versa? Any thoughts?
I made a research in internet, but there`s not much about it. Please, feel free to comment whatever you find in charge with the topic. 
Or, if you want, you can share if you and your partner personaly have major differences between synastry and composite.
The composite chart is a picture of the energies and dynamics when you are a couple. Treat it as one unit, one person. Being a couple is never without its challenges. So if you see something that looks like a hard aspect, then you have a heads-up and can use various tools and approaches to manage it, to know what you're up against.
How the relationship will work will depend on the two of you. The chart is a tool to help.
Vivid-shi, it will work anyway as long as you don't let the harsh moments get to your head Think of harsh aspects as tools... Imagine to wake up in bed with your partner and find out there's a chainsaw among the sheets!! Would you fight over who gets to keep that and use it to chop each other to pieces, or sit down and try to address the subject to analyze the situation and find out who put it there? Challenging aspects in both Synastry and Composite can be great tools for the maturation of a relationship PROVIDED THAT - as always - other aspects indicate that the potential for a relationship is there, and you mentioned them.
The difference would be that, in Synastry, an aspect can indicate what comes from who and upsets who (sort of)... in composite, the POSSIBLE issue is simply given by the interplay of energies so it's fed by both. But really, as Allie said, do you actually know a couple who doesn't experience challenges? Nothing can always be smooth... unless you base your relationship on soccer, pizza and beer 😀
Thanks, your comments are very helpful.
But generally, I was speaking for different thing: I mean when in the composite are such a challenging aspects...is that mean that the couple will separate after a couple of months? Because now I found one topic, in which other people said that especially with the Moon square Saturn/Uranus, it will "ruin'" the relationship.
And I`m asking in general, not only for the composite with this boy. I mean : is there such a thing in composite (or synastry) that can tell: "these two people will separate!This relationship it`s not going to work , because of this or that aspect"?
And do you two have some challenging aspects in yours composite with your partners? And how do you feel it?
No, I don't think you can look for astro-markers for that in a synastry/composite. In the same way I can't tell from a chart if the native will get sick with an incurable disease and die, or kill his heighbours or win the lottery. What causes two people to part ways, is their attitudes and behaviours towards each other. Lack of understanding/acceptance, lack of sexual chemistry, lack of dialogue, lack of sincerity... However, make acceptance, understanding and dialogue the ingredients of a relationship and you'll fare decently as long as it lasts.