Short answer
Couples should discuss intimacy privately, respectfully and without accusations, comparisons or insults. The aim should be understanding and cooperation rather than winning an argument.
Islamic Guidance
What Islam teaches
Islam emphasises kind treatment between spouses. Sensitive marital matters should be handled with dignity, privacy and consideration.
Practical Guidance
What you can consider
Choose a calm time, use statements such as 'I feel' rather than blame, listen to the other spouse, and agree on practical steps together.
Sources
Qur'an 4:19; Qur'an 30:21.