So what is the atheist position on marriage and extra-marital sex and fidelity?
This seemed to be directed at me.
Marriage:
http://www.sciforums.com/showpost.php?p=2582535&postcount=15
Fidelity: Fidelity is defined as loyalty or faithfulness. I don't think that fidelity on it's own can be considered a valid moral foundation - for instance, loyalty to the immoral is certainly not an honorable behavior. Loyalty within an intimate relationship, however, has its benefits.
Love: There are various types of love, from the general empathy for other living things that most people have to a certain extent, to the burning self-sacrificial attachment a parent has for their child. The strength of the connection between two adults can be a very powerful and beneficial thing, improving the quality of life for both individuals. This connection need not be limited to intimate individuals, but can extend to a group of strong friendships which create a strong social group. When it is stronger than the love of friendship, there is potential for even more benefit for the people involved, but it must be approached carefully.
In general, love if founded by compassion; for the shift of focus from selfish desires for your own happiness to a desire for the happiness of another. Pure love would be the perfection of this state of being; loving all others are yourself, and hating all suffering by all beings as strongly as you detest you own pain. This is really hard to do; it is not our natural state of being.
Extra-marital sex: Physical intimacy is one part of a larger set of behaviors which are risky but potentially rewarding. The risk/reward of each behavior needs to be inspected, and carefully approached to maximize the benefit for each person while minimizing the potential risk. Opening oneself emotionally to another person is very risky, but has the potential for a the creation of a wonderfully sustaining relationship of trust between people. Sex, similarly is potentially risky, but can provide great rewards when handled responsibly. In both cases, the most important part of acting responsibly is choosing your partner wisely. Realistic and brutally honest consideration of the chances of being hurt, and of the chances for your own imperfections hurting them (and thus yourself as well) is necessary.
Particularly for the woman, whose personal space/physical body is invaded (Guys, think about someone else sticking their finger in your nose. Don't like the idea? Yeah.), sex can have very powerful effects, not even considering the chances of pregnancy and disease. Irresponsible use of sex can cause severe emotional or physical distress, create addiction and destructive dependency, and even create life-long damage.
Conclusion: In my personal exploration of this, I have concluded that while intimate emotional and sexual relationships do not have to be monogamous in order to be healthy and fulfilling in theory, the complexity of having multiple relationships of that kind is in itself likely non-tenable, for two main reasons: jealousy and emergent complexity.
While multiple people, in theory, could all be responsible individuals acting for the benefit and happiness of all others in the group at a perfect level of pure compassion and affection, humans are generally not capable of such behavior. Due to this, selfish wants for more of a certain person in the group will likely lead to factions and jealousy and frustration and anger. In addition, unpredictable or perceived negative events which unbalance the factual situation of individuals in the group in emergent ways, can cause some members strife, which in turn will cause annoyance towards the member who introduced that "problem" - likely also resulting in factions, jealousy, frustrations and anger (in this case, I'm specifically thinking of what would happen if one person caught a disease and either spread it to the rest of the group (leading to anger), or that person was cut out from the group due to the potential for spreading disease (leading, again, to anger)).
It seems to me that selfish human desire would prevent the long-term existence of a healthy intimate multi-party relationship.
Given the difficulties of life, it is even hard to manage a single healthy intimate relationship; monogamy is not, to me, a godly decree or a moral absolute: it is the likely highest level of complexity that the human being has a chance of making work during a single lifetime. A devoted promise between two individuals to focus attention and love on only each other has, in my mind, the most realistic chances of providing the benefits of intimate emotional and physical connection with the smallest risk of contracting disease, having accidental children that can't be cared for, or being hurt emotionally in a permanently damaging way; generally by limiting the action of jealousy and the risk of introducing outside unbalancing influences (such as disease).
Love vs Marriage: Marriage is an artificial construction, a ceremonial public promise. Honest love is the natural, meaningful act of caring more for another than for yourself, and to me, the only thing really worthwhile. Marriage requires love, love does not require marriage.
Greater love and celibacy
There also exists a downside to creating a single point of focus for one's intimate love. By choosing to love one person more than all others, you build a wall between yourself and the rest of humanity. True and pure perfect love, IMO, *must require* the lack of such walls, and therefor to me, the lack of such a choice. For about 6 years, I chose to avoid intimate relationships for the sake of loving all of humanity; for the hope of devoting myself to helping all of humanity. Then my father pushed me into trying to have an intimate relationship one last time, and I met my "girlfriend"/effective wife. I have for her, all devotion of a husband, and I maintain that by choosing to be selfish daily - doing what makes me happy (loving and caring for her), rather than what I feel to be morally nobler - the sacrifice of my own desires for the sake of devoting everything of myself to helping other suffering beings.
As an atheist, do you believe in a conscience?
I don't have to believe in it, I have it. I can test and verify it by acting selfishly and selflessly, and seeing how such behaviors effect my emotional state.