Short answer from Jain dharma: It is not recommended.

Why

• For householders, the brahmacharya-anuvrata teaches modesty (lajjā) and restraint (saṃyam). Sleeping naked can provoke sensuality (kāma) and negligence (pramāda), making self-control harder. Simple, modest night‑clothes support inner discipline.
• On vrata/utsav days (e.g., Paryushan/Das‑Lakshan), during fasts, or while observing special brahmacharya practices, greater caution is expected—avoid anything that stirs passions; many families even keep separate bedding on such days.
• For ascetics, complete celibacy is mandatory; this question does not apply.

Digambar and Shvetambar views

• The difference in monastic dress (Digambar sky‑clad; Shvetambar white‑clad) is for monks/nuns and symbolizes renunciation. It does not permit or encourage nudity for lay couples. Both traditions expect modesty and restraint from householders.

Practical guidance for a Jain couple

• Wear clean, loose, simple night‑clothes.
• Keep the bedroom plain; avoid stimuli that excite the senses.
• Observe periods of abstinence as guided by your ācārya/upādhyāya and family tradition.

For quick study on lay vows and sexual restraint:

• Anuvratas and brahmacharya for householders
• Swadara‑santosh and Maithun‑virama (limits for grihasthas)
• Overview: Jain view on sexual conduct