Differences in how much and when two people feel warm or cold may be part of the chemistry that draws couples together. But those differences can be quite a problem when a couple shares a bed.
Let's say she often feels cold, that her hands, feet, face, and whole body are often cold, even painfully so, particularly in winter. (In the interviews I did for my Two in a Bed book, in heterosexual couples the woman was three times more likely than the man to be the colder one.) As they first get to know each other she may be drawn to his warmth, not only feeling romantically drawn to him but also delighted to have his warm hands holding her cold hands, his warm cheek against her too-cold cheek, and the warmth of his body diffusing into her body as they cuddle. And he may love it that she so enjoys being touched by him. But when they become a bed-sharing couple, they may have big conflicts regarding the temperature in the bed and the bedroom. Temperatures that feel comfortable to her may feel suffocating to him. Temperatures that feel comfortable to him may feel painfully cold to her, so cold that she aches and feels numb. What can they do?
There are couples who battle for years about thermostat settings -- thermostat wars in which each sneaks to the thermostat to set it up or down when the partner isn't paying attention. But many couples agree to a compromise setting that neither particularly likes, or they agree that one of them is in charge of thermostat setting and the other partner just has to live with whatever the setting is. Whatever a couple does about the thermostat at night is usually related to what they do about blankets, snuggling, windows, what they wear to bed, and maybe much else.
How Many Covers to Have on the Bed
Many couples who share a bed go to bed and to sleep under shared covers, but that can be challenging for couples with big differences in temperature preferences. If they are under shared covers that might be too warm for one partner and not warm enough for the other. So some couples arrange for extra covers on the partner who is more cold-sensitive. Also, the partner who is more heat sensitive may push covers off or sleep with parts of him or her not covered--often with feet sticking out from under the covers. And then some couples use electric blankets with dual controls, so they can set their blankets to different temperatures.
Sometimes the partner who is too cold may steal covers from the warmer partner, maybe even doing that while asleep. If cover stealing is a problem for you or your partner, that might be a sign that the "stealer" needs more blankets at night. (But then it might also be a sign that the "stealer" just holds on to covers while rolling over.) At any rate, one way to head off cover stealing is to tuck the covers in on the side away from the cover-stealer, so it would take enormous strength to actually steal them.
Icy Feet, Hands and Everything Else
Often a person who is cold sensitive is particularly uncomfortable and cold when first going to bed. No matter what else a couple does about night time temperatures, they may need to do more when the cold sensitive partner comes to bed. Often the warmer partner provides personal body heat to the cold partner. The two may snuggle up in a way that might seem to be romantic or sexual but is very much about warming cold feet, hands, legs, and behind. Ideally, they do that snuggling on the colder partner's side of the bed, so the sheets and blankets on that side of the bed are also warmed by the warmer partner. It can be quite painful for the warmer partner to have the colder partner's icy feet between his thighs, but then he may be proud to be his partner's personal heater. Some warmer partners also get in bed before the colder partner does--on the colder partner's side of the bed -- to pre-warm that side of the bed.
Windows, Heaters, Air Conditioners, and What to Wear to Bed
Potentially there is a lot else that a couple can do to make their shared sleeping situation comfortable for both of them. For example, the partner who is more cold sensitive may do better sleeping farther from a window air conditioner and closer to heating ducts or radiators. The partner who is more heat sensitive might do better to wear skimpier bed clothing or go to bed nude, while the cold sensitive partner might wear socks and several layers of sleepwear to bed. And there are many other options involving hot water bottles, pets, the kind of sheets people sleep on, space heaters, and so on. The bottom line is that for couples with real differences in temperature preference, there is problem solving to do. It may be challenging to get things right, but many couples eventually find fixes that work well for both partners.