In relationships, someone with Jupiter in Capricorn tends to show love through doing. They fix things, provide, sort out problems, settle the bills, and plan the logistics of a holiday six months ahead. What comes harder is saying "I love you" out loud, or admitting they've missed someone. I often watch the partner of such a person spend years quietly feeling unloved, when in fact they're being cared for in a thoroughly substantial way — it's just that the language of that care is an unfamiliar one, written in deeds rather than words.
This placement tends to need a partner who can read actions and doesn't ask for constant verbal reassurance. A very expressive companion who needs daily declarations may wear them out quickly. But a wholly cold union doesn't work either: inside the dry shell there's usually a child who had to grow up too early, and it matters a great deal that at least one person sees them as something other than a job title and a list of responsibilities.
The weak spot is the habit of postponing closeness to some later date. First we'll finish building the career, then we'll clear the mortgage, then the eldest will finish school, and then — then we'll go away, just the two of us. That "then" has a way of never arriving. Without some ritual of warm presence in the here and now, the relationship can drift, over years, into the joint management of a household: efficient, reliable, and quietly short on tenderness.
With children, people with this placement tend to build the vertical — education, tutors, a solid foundation. The blind spot is missing that a child might want, not preparation for the future, but simply a game on a Saturday. It tends to help to mark out hours when you're deliberately not the strategist-parent but the adult who plays daft card games on the living-room floor. Without those hours, a child can grow up with the sense that the love was conditional, earned through good marks. None of this is set in stone — it's a pattern to watch for in yourself, not a fate you're locked into.