Wherein we discuss the finer sex.
Unlike the original rules, there is now no limit on how high a mistress you can court: the base die roll is the SL difference if it is more than 6. The maximum you can pay is 15*her SL (which reduces the base roll by 4). So unless you win a duel, you won't have any chance of courting her if the difference is more than 10. For each duel you win on the doorstep that week your required roll is reduced by 1, but she'll still reject you on a 1. If you are allowed to not fight the duel on grounds of low endurance, then you may do so and not incur the standing down penalty as well.
To propose to a mistress you must have been going out with her consistently for six months (more precisely she must have been your mistress since the start of the month six months previously). A proposal attempt takes a week and costs 15*her SL in crowns. The chance is that of a normal (unmodified) courting attempt. If you roll a 1, there is a 1 in 2 chance that she will dump you altogether.
If your proposal is successful, you must announce a wedding date, usually the following month. The week of the wedding includes a stag night (a party hosted by the groom for which he will pay all costs). When you marry you will receive a dowry of d6*25*mistress SL in crowns, doubled if she is wealthy. The husband automatically goes up an SL he month he marries.
The wife of a PC will increase her SL by one if her husband accumulates SPs >= 4 * her current SL in one month. Her influence will increase to that appropriate to her new SL.
A married mistress may be courted for a one-week relationship: this is a normal courting attempt with a penalty of 2, and the roll may not be reduced below a 4. If you fail the roll and are discreet, nothing happens. If not, then the husband has cause for a duel. If you are successful then what happens next depends on whether you are discreet about it or not (you may choose to be indiscreet if you wish).
If you are discreet, then you get FC but no SPs, and the husband loses 3SPs (rumors and whathaveyou).
If you are not discreet, then you get the SPs for the mistress, the husband loses 1/2 of his SL in SPs and has cause for a duel. [We may make this less if the husband is at the front]
If successful, there is a 1 in 6 chance that the wife will fall madly in love with you and things get horribly out of hand. In this case the wedding is annulled and all three parties lose an SL as a result of the disgrace (and the ex-husband has cause).
Married men may not court other women (or rather if they try and are successful or indiscreet nasty but as-yet-undecided things will happen to them).