The only solution to desire discrepancy, say the experts, is to avoid pop psychology jargon and talk openly, directly, and honestly about your sexual needs. But until they actually talk about it openly, it remains a hidden agenda, and often a source of frustration and shame. That's simply not healthy in any sense. Nor is it typically easy to establish this open communication. They may be masters of business communication, but unable to discuss what really matters to them personally.
Sex is obviously far more than the simple intercourse.
Four times a week seems right for many couples. This may not mean having intercourse. Maybe they just sit together and watch television and hold hands at first. Or perhaps they agree to caressing the arms and legs of the other in turn. Often it is this sort of small time together that helps re-establish the joy and affection that's needed as a prelude to intercourse later.