Saying yes to the same things
One mentions the light looks amazing and they should drive to the coast. The other already has their keys. Two ISFPs share extraverted sensing (Se), a delight in color, taste, music and movement, and both like leaving room in the day for whatever comes up. Dates are often things: a pottery class, a long cook, a concert they found that afternoon.
Both lead with introverted feeling (Fi), so each respects that the other has private values that don’t need defending. Neither tries to remake the other. That acceptance is one of the most comforting things an ISFP can find.
Two people in two quiet rooms
The risk comes from sharing the same retreat. When an ISFP is hurt, they tend to go quiet and step away rather than argue. With two, a disagreement can end with each in a separate room, both waiting for the other to come out first. Days can pass. Since both assume their own values are obvious, each may also believe the other agrees on something they’ve never discussed, like whether to have children or where to live.
Practical life is the other shared gap. Extraverted thinking (Te), the planning and organizing function, comes last for both. The spontaneous coast trip is wonderful until the credit card bill arrives, and neither of you has looked at it. Two ISFPs can be happy and free for a long time while savings, paperwork and long-range plans quietly pile up.
Who comes out first
Agree in advance that after a fight, whoever is ready first goes and knocks, and the other answers honestly. If saying it is hard, writing it works too. Discuss the big values early and out loud, even though it feels unromantic.
For money and logistics, a monthly hour together with a simple checklist covers most of it. Treat it as part of protecting your freedom: the bills that are paid on time are the ones that never interrupt the coast trip.