Try to agree who keeps any pets. Consider the cost of keeping them such as food, vets' bills and insurance, and also think about whether you can meet their welfare needs, for example if you work long hours and do not have time to walk a dog.
If you need to move into rented accommodation, be aware that landlords often do not allow pets. If you decide neither of you can keep your pet after you separate, look for a responsible local or national re-homing organisation (see Useful links).

Anne