I am currently reading The Art of Communication by Thich Nhat Hanh and going through some rough spots in a relationship.
From a Buddhist perspective, what is the most loving way to communicate, in a relationship when both people are suffering and have opposite needs? One believes they need space to heal and find themselves, and the other needs understanding that comes through meaningful communication before that time apart will seem restorative.
Buddhism always recommends truthful (sacca) & gentle (soracca) speech in relationship.
Three other qualities emphasised are: (i) training (dama) in self-improvement; (ii) patience (khanti); & (iii) sacrifice (caga). See link.
At this time, the above qualities are obviously crucial in your 'rough spot'.
However, the most important quality of relationship in Buddhism is 'mutual or same needs'.
Householders, if both husband and wife wish to see one another not only in this present time but also in the future, they should have the same faith, the same virtuous behavior, the same generosity and the same wisdom.
Both husband and wife are endowed with faith, charitable and self-controlled, living their lives righteously, addressing each other with pleasant words,
Then many benefits accrue to them and they dwell at ease. When both are the same in virtue.
A commentary on this teaching by Thailand's foremost scholar monk is below:
The compatible couple: there are principles for partners in life to ensure their compatibility, providing a firm foundation for a long married life, called the four qualities for a good match (samajivi-dhamma):
1. Sama-saddha: having compatible faith; they uphold the same religion, revere the same objects of worship, concepts, beliefs or principles, and share the same lines of interest - they are equally firm in all these or can reach agreement on them.
2. Sama-sila: having compatible morality; they have conduct, morality, ethics, manners and upbringing which are harmonious or compatible.
3. Sama-caga: having compatible generosity; they are in accord, not conflict, with each other in their generosity, hospitality, munificence, sacrifice, and readiness to help others.
4. Sama-panna: having compatible intelligence; they are sensible and can understand each other; they can at least reason with each other.
A Constitution for Living: Buddhist Principles for a Fruitful and Harmonious Life
Without same needs or goals, Buddhism would say a relationship is difficult to maintain.
"Love" seems to me to be quite an ambiguous word in English ... for example, depending on who's saying it, "I love you" might mean "You give me what I need", or, "I give you what you need."
Brahmaviharas
One of the recommendations about "being loving" is the doctrine of the Brahma-viharas ... for example, this essay introduces them by saying,
These four attitudes are said to be excellent or sublime because they are the right or ideal way of conduct towards living beings (sattesu samma patipatti). They provide, in fact, the answer to all situations arising from social contact. They are the great removers of tension, the great peace-makers in social conflict, and the great healers of wounds suffered in the struggle of existence. They level social barriers, build harmonious communities, awaken slumbering magnanimity long forgotten, revive joy and hope long abandoned, and promote human brotherhood against the forces of egotism.
The Brahma-viharas are incompatible with a hating state of mind ...
I think they're all worth considering. If your partner becomes more enlightened then that would be occasion for mudita, for example.
The recommendation that these are right attitudes isn't specific to people who are "in a relationship" but, given they're for "all situations", that includes someone with whom you have a relationship.
Traditional responsibilities
The suttas include advice for married couples, including a definition of responsibilities ... the duties of the husband and the duties of a wife.
I'm not sure it's sensible (I doubt it's sensible) to have these expectations of your partner if they're unwilling (i.e. if you don't see things from the same perspective).
To the extent that people do have needs, expectations, and duties, I think they're supposed to have different kinds of needs: e.g. what children need (and what your duties towards them are), is different from what your wife needs, your employees need, your parents need, and so on.
I think it's easy in modern society for a couple to try (and fail) to be all things to each other.
Not
Notwithstanding the Brahmaviharas, it seems to me that many Buddhist qualities or ideals are defined as a "not": for example, being "harmless" (Avihimsā, also translated as "friendliness or "absence of cruelty"); or, "attachment" (desire, clinging) is seen as a cause of suffering, so conversely non-attachment is a good thing.
Similarly I think that being selfish (which I think includes having views such as "I need this" and "I need that", and "I need you" and "I need you to do this and that for me") is going to be counter-productive to the aim of reducing suffering.
Expectations
There's a bit of advice in this answer about what to look for in a marriage partner.
If I may say so I think I might interpret the subject of "needs" a little differently than Dhammadhatu does. One of the foundational virtues is "generosity" (i.e. giving), which might be seen as almost the opposite of being "needy".
I expect young children (infants) to be "needy", I kind of expect adults to be the opposite of needy, i.e. generous and independent.
Specifically
You said that the two of you have "opposite needs".
My theory is that you would do better if you were less needy, or at least more independent at satisfying your own needs.
I actually see each of those needs in isolation (rather than being in opposition to each other).
One believes they need space to heal and find themselves
I'm not sure there is a "self" to find (so this "need" might be either doomed to failure, or at least badly expressed).
What more likely I think is that this one has a current view-of-self which they don't like (a view that's self-imposed and/or which their partner is trying to impose on them).
I suspect they might not "find themselves" but do want to escape from a view-of-self which they find constraining. For example if they're being told "You don't meet my needs", that's disparaging (their partner might do better to, instead, encourage what they're good at).
the other needs understanding that comes through meaningful communication
Three theoretical problems I foresee with this include:
