Lama Ole’s answer:
This depends on the quality of the relationship between the partners. Nobody benefits from ill-tempered, joyless parents who feel like victims because they had children together at some point. In my opinion, this is an escape from life. Neither the partners nor the children feel good about that. Children get along better with a single parent than with parents who argue or even play their children against each other. This way, they can be together with one parent and then the other, as they like.
If the children are small, it is best to try to stay together at first. If this doesn’t work, they should separate rather than gluing together something that doesn’t fit. They should never forget to speak nicely about each other, and for that, a certain distance is essential.
Sometimes people come together only as a result of their shared karmic debts. They make love on a hot summer night, the woman gets pregnant and has the child, and all of this is because of old karmic debts that need to be paid to another being. In this case, they have to work with it as well as possible, but the situation shouldn’t make them and everyone else unhappy.
I would check whether my partner is my friend—whether we are developing together and making good wishes for each other, or whether he or she can only see me in a restricted role. On this basis, you can decide what you want to do. This life is only one among countless lives, and since that’s the way it is, one has to think beyond the present lifespan. What matters in the long run is real development.
No doubt, for the spiritual development of the partner and the children, it’s best if both parents are around and share the work. One parent might look after the children while the other has time for meditation. This way, we don’t have to cut back in any way. We can even develop well, which in turn benefits everybody.