Personal vs outer planets in synastry

What if you have pleasant aspects with someone's personal chart (mars conj venus) but not with his outer planets like mars opp saturn.

I thought it means you generally get on well except when he has harsh transits. What do you think?

I've just read an interesting explanation about this: it says good personal planet aspects in a relationship are for high-school love when you meet and have a good time. But with time you grow apart (Saturn opposition?).

It is the same with all the outer planets (in case of Uranus squares/oppositions when your independence is threatened by the other person, or Pluto when power struggles get in).

It makes sense to me.

Have you checked these outer planet things in your relationship?