This is an extremely sensitive issue and despite getting on well on a day-to-day basis, it may be that your relationship declines to the point of separation due to sexual incompatibility.
Everyone has their own level of sex drive and it may be that your partners greatly exceeds yours or is totally insufficient for your needs. This can lead to extreme anguish and intolerance and in many cases can drive separation. It is very common for couples to 'avoid' talking about such issues for fear of 'rocking the boat'. The consequence is very often that unexpressed feelings can lead to bitterness, resentment and a general deterioration in communication, often ending in a complete breakdown in the relationship. This could all be avoided.

If you have separated or are considering doing so with sexual incompatibility being the cause, it is essential that you take some advice before committing to a permanent separation or divorce. There is no need to end what may be a perfectly good relationship where a solution can be found.
A counsellor will be able to help you as a couple to discuss each of your expectations and feelings and it may be that you could also see a counsellor individually if preferred.