colette definitely does not sleep well as the dark urge. especially if she begins to resist it. like if she doesn't completely satisfy the urges with killing and slaughtering her enemies, she definitely is afraid of what will happen when she sleeps. especially because the last time she fell asleep, she killed alfira. like. that fucked her up for the longest time. she didn't eat, didn't sleep, was afraid of touching anyone for the longest time.

and even still, if her partners know about her dark urges, she's still frightened to sleep with them, to try and be with them intimately because she's afraid that she will hurt them or kill them. she knows that her father could likely take control of her at any moment if she continued to resist and just take what she loved from her.

that's why i think she doesn't initiate into a true relationship until late stages of act 2 to mid stage of act 3. after she's free from bhaal, that's the only time she allows herself to truly be free.

otherwise, i think she's very much so touch starved, wanting to be with someone but too scared to do such.