This answer is based on religious scriptures and traditional and modern teachings of morality, religiosity and spirituality.
As far as food and gifts are concerned there is nothing specifically wrong from spiritual angle in accepting food or gifts from others.
In our tradition, “non-acceptance” of gifts (or food) is that which renunciates affirm as an aspect of the yamas described in the eight fold Patanjali’s Yoga Sutras. We consider accepting anything without purity and sanctity as not good.
Everything depends on the attitude of one who offers food or gifts to another and the attitude of one who accepts the food or gift. This can get exceptionally complicated. But if your wife or mother or sister or a real well wisher gives you food, it is fine and acceptable.
If you receive food or gifts from someone who is wanting to receive favour and get in your good books for selfish or improper reasons, then you may have incurred an obligation that you do not want. In such a case, you should not certainly accept the food or gifts.
If you accept food or gifts from someone who does not respect or love you or who is of lower consciousness, then you should think twice before accepting them.
Regarding multiple affairs, this is forbidden by all the scriptures and saints for both sex because indulging in sex for the sake of physical and mental pleasure alone is a form of adultery because “adulterating” the true purpose of sex: to have children or to express love and commitment and not merely pleasure. By this act one disrespects soul’s true nature and that of the partner by going after sexual pleasure for its own sake. It amounts to worship of the human body: a “false idol.”
Sexually transmitted diseases; hurt feelings; abuse; disrespect; guilt consciousness, dishonor, remorse, disgust, loss of vitality, boredom; anger; untruthfulness; crimes of passion; low esteem, drunkenness; so many negative actions, feelings and emotions are potentially aroused by excessive and promiscuous sexual indulgence.
Our Vedic scriptures consider Adultery as one of 5 Great sins (Pancha Mahapadaka) without remedy, promising great suffering in hell for a very long time due to the effect of bad karma. Similarly One of the Buddhist scriptures,
Maha Kammivabhanga Sutta says:
The Blessed One said, “Ānanda, there are four kinds of person to be found in the world. Which four? There is the case where a certain person is one who takes life, takes what is not given (steals), engages in illicit sex, lies, speaks divisively, speaks abusively, engages in idle chatter; is covetous, malevolent, & holds wrong view. With the breakup of the body, after death, he reappears in a plane of deprivation, a bad destination, a lower realm, hell.
Scriptures also point out, that the results for cheating and adulterating are
* Going trough a Transsexual phase (Shemale)
* Being born in hell
* Even after many lives, not being able to live a happy married life
* Even after many lives the partner losing interest in or not being loyal to this person
* Being born with a mutation or defect in the gender defining area
* Getting birth among animals who kill other males to have dominance over the females (Example -Monkeys)
* Born with a character that does not fit the gender (Men who act like women, Crossdressing)
Karmic impact of womanising, adultery or multiple relationships involving hurts are very complicated and often resulting in suffering from incurable physical and mental diseases during or at the end of one’s lifetime. Karmic negative impacts also include one or more of the following major negative effects:
Children (and grand children) not getting married or not happy in marriage.
[This also makes sense from the practice, that grand children or children inherit all material possessions of Grandparents or parents through a will or by order. When they can inherit material possessions, karma and their effects of Grand parents (or parents), which can be arising from sin or merit also being subtle material possessions of them, will reach the children (or grandchildren) by divine order.]
Loss of wealth and liquidity crisis.
Children (grand children) not getting children or lineage not expanding.
Generational suffering through separation, childlessness and/or lack of peace and happiness.
And falling from Grace, going to lower births or hell (as per scriptures)
Promiscuous and deliberate sexual activities and multiple partners strengthen the ego consciousness and the senses upon the mind. The real purpose and place of sex in human life is in the context of love not merely pleasure.
When we abuse our body by over indulging in sex, we tend to alter the DNA code of our physical body due to mutual energy transfer, affecting our astral-plane mapping however the outcome is dependent upon the extent of the abuse to our physical body. All the genetic code that people who are reborn which carries mathematical precision. We may be reborn into a family where a particular chromosome is reactivated to excessive sex. In this way hereditary is influenced with sexual karma.
The pleasure from lustful adultery is momentary or fleeting, yet the sinful karma it brings is very large. Among those who commit lustful adultery, some may die as a result, some fall from senior positions, some ruin their own families and some become childless. Some may be predestined to enjoy great wealth and fame, but if he commits lustful adultery, he may become poor and miserable all his life. A person may be predestined to have good longevity and have great fortune, but if he commits lustful adultery, he may become injured or sickly and die at an early age. A person may be predestined to have a faithful wife and a virtuous daughter, but if he commits sinful adultery, his loved ones may also become unfaithful and lustful.
It is always better to seek a good or suitable life partner whom one can mutually love and respect. There are many yogic, Vedic and traditional methods of re-directing the sex energy (the divine gift) into positive directions: meditation, exercise; diet; music, dance, pets, sports and games and the arts; devotion to God; service to humanity; creative and wholesome activities and so on. Transcendental Meditation, Bhakthi and yoga and interestingly advanced mudras, pranayama and kriyas are very helpful when practiced with the guidance of a Acharya or guru and with utmost devotion.
One should approach a competent Guru and seek his or her company and counsel to receive the appropriate techniques and knowledge for the conscious recognition, rectification and removal of such attitudes and behaviours that tempt one into such improper, inappropriate, unfulfilling and false relationships and thereby freedom from lust is achieved and also resulting in ascent of divine Grace.
Let us pray to Almighty, compassionately for the restoration, peace and change in attitude of people having such issues.
Let us also learn to forgive.