| Model 1 | Model 2 | |
| OR (95% CI) | OR (95% CI) | |
| Background characteristics | ||
| Age (years) | 0.99 (0.96 to 1.01) | 0.98 (0.96 to 1.01) |
| Region | ||
| North (reference) | 1.00 | 1.00 |
| Central | 1.24 (0.66 to 2.35) | 1.07 (0.56 to 2.06) |
| South | 1.87** (1.02 to 3.45) | 1.72** (0.91 to 3.25) |
| Trajectory membership | ||
| Sexual debut ⩽15, married 1st sexual partner | 1.85 (0.98 to 3.49) | 1.87 (0.98 to 3.58) |
| Sexual debut ⩽15, did not marry 1st sexual partner | 1.43 (0.76 to 2.70) | 1.22 (0.63 to 2.36) |
| Sexual debut >15, married 1st sexual partner (reference) | 1.00 | 1.00 |
| Sexual debut >15, did not marry 1st sexual partner | 2.59** (1.30 to 5.16) | 2.52** (1.25 to 5.10) |
| Characteristics and behaviours of sexual and marital partners | ||
| Total number of lifetime partners | ||
| 1 (reference) | 1.00 | |
| 2 | 2.24** (1.25 to 4.03) | |
| ⩾3 | 2.56** (1.34 to 4.90) | |
| Was part of least one polygamous union | 1.54 (0.93 to 2.54) | |
| Had EMSP during any marriage | 0.94 (0.44 to 2.02) | |
| Knows at least one husband had EMSP | 1.00 (0.99 to 1.00) |
CI, confidence interval; EMSP, extramarital sexual partner(s); OR odds ratio.
Differences in the likelihood scores between models 1 and 2 with 3 degrees of freedom were statistically significant (difference in 2-log likelihood = 24.37; df = 5; p<0.001). Model 2 therefore provides a better fit.
**p<0.05.