Lewis & Short

cōnūbĭālis (less correctly connū-bĭālis; in the poets gen. to be read as four syll.; cf. conubium; only in Claud. Ep. 2, 18, cōnŭbiālis), e, adj. [conubium], pertaining to wedlock, connubial, conjugal (poet.; perh. first used by Ov.): jura, Ov. H. 6, 41: vincla, Stat. Th. 5, 112: carmen, Claud. IV. Cons. Hon. 651: vectigal, id. Epist. 2, 18: foedus, Salv. Gub. 7, p. 244.
* Adv.: cō-nūbĭālĭter, in a conjugal manner, connubially: procum allegaret, Mart. Cap. 6, § 576.