Taurus · Taurus
Nothing here is going to move unless one of you moves it.
Two Taurus Suns is one of the most comfortable pairings there is, and comfort is exactly the risk. The same pace, the same appetites, the same view about what is worth spending money on. Also the same refusal to be the one who changes anything, ever.
What pulls
The absence of friction, and it is a real pleasure rather than a compromise. No one is being hurried. No one is being asked to be more spontaneous than they are. Food, money, sleep and touch are all being taken as seriously as they deserve, by two people who have both been told at some point that they are boring by someone who was exhausting.
Where it grinds
Fixed earth does not initiate. So when something needs to change, and eventually something always does, both of you wait, quite patiently, for the other one to raise it. Weeks pass. The thing does not go away, it just goes underground, and comes back as a mood about something else entirely. Neither of you is avoiding the conversation exactly. Neither of you is having it either.
The long version
Forty good years or a very well-appointed rut, and the difference is not luck. It is whether anything in either chart is willing to disturb the surface. That is exactly the kind of thing two identical Sun signs cannot tell you, and a Mars or a Uranus contact between the two charts absolutely can.