He thinks I should quit my job after kids, but I love my career. Is this a dealbreaker?

This difference in expectations about your career after having children is indeed very significant, and it's wise that you're recognizing its weight now. It's not just about a job; it's about your identity, financial independence, daily life, and the division of responsibilities within your future household. You need to delve deeper into what "quitting your job" means to him. Is it a temporary break, or a permanent end to your professional life? What are his reasons for this expectation? Similarly, you must clearly articulate what "continuing your career" means for you – full-time, part-time, working from home, or pursuing specific professional goals. Explore if there are any middle grounds or compromises that genuinely satisfy both your aspirations and his expectations, without one person feeling resentful or unfulfilled. It is crucial to have these detailed, honest conversations now, before you proceed further. This is a fundamental aspect of your shared future that rarely resolves itself or changes once marriage and children are in the picture. Confronting this now, even if it feels challenging or uncomfortable and potentially means rethinking the match, is far less costly than discovering an irreconcilable difference after commitment and family involvement. Your long-term happiness hinges on alignment on such core life visions.