A system for additively manufacturing a composite part comprises a delivery guide and a surface, at least one of which is movable relative to another. The delivery guide is configured to deposit at least a segment of a continuous flexible line along a print path. The print path is stationary relative to the surface. The continuous flexible line comprises a non-resin component and a photopolymer-resin component that is partially cured. The system further comprises a feed mechanism configured to push the continuous flexible line through the delivery guide. The system further comprises a source of a curing energy. The source is configured to deliver the curing energy at least to a portion of the segment of the continuous flexible line after the segment of the continuous flexible line exits the delivery guide.