Sun in the 2nd house synastry means their Sun falls in your 2nd house: where their identity lands in your life. What it feels like from both sides, the gift, the shadow, and how to find your overlays.
Sun in the 2nd house synastry means their Sun falls in your 2nd house: money, possessions, self-worth and the feeling of having enough. Their identity lands in the part of your life that keeps the lights on. You tend to see them as a source of security, and they tend to feel valued when they are providing or building something with you.
Their Sun in your 2nd house
For you, this person changes how you feel about what you have. Conversations drift to rent, savings, the price of the sofa, whether the job pays enough, and you find yourself wanting to earn more or spend better around them. Their opinion of your worth carries unusual weight; a passing comment about your salary can land harder than it would from anyone else. For them, your world is a place where they feel useful and solid. They like paying for dinner, fixing your bike, splitting the shopping, helping you negotiate a raise. Their sense of self gets tied to being the one who adds value in your life. The classic pattern is a couple who talk about money early and often, sometimes before they have talked about feelings.
The gift
Steadiness. You get a partner who makes your material life feel warmer and more possible, whether that means a joint savings goal or simply someone who remembers you like the good olive oil. Their presence helps you value yourself more; your self-worth rises in their company. They get to be appreciated for what they build and provide, which for many Sun people is the sweetest form of love. Shared purchases tend to go well, and you can plan a year ahead together.
The shadow
Possessiveness, in both directions. You can start treating them like an asset, something owned, and feel threatened when they spend time or money elsewhere. They can start keeping score of what they have given and expecting your gratitude. Arguments about money often stand in for arguments about worth: who contributes more, who is taken for granted. If their income or generosity dips, you may feel less secure in ways that seem out of proportion, and they may feel their self is being weighed.
Working with it
Say thank you out loud for specific things, not general ones: the coffee, the lift to the station, the hour they spent on your tax return. Keep some money that is only yours, even a small account, so security does not depend on them. When a money fight starts, pause and ask what each of you is really afraid of losing. Let them provide sometimes without turning it into a debt, and provide for them sometimes so the flow goes both ways.