Question

@sensibleApple9556

There is a lot going on in the bedroom when you're having sex than just sex and hopefully the mutual orgasms. Foreplay can be, in some cases, more important than the sex itself.

I think it should be said that sexual connection throughout the week is just as important as the physical act of sex itself. Just as you've said, the touching, hugging, spending time, kissing, dates (even if you're married or already in a relationship), and so on are all important ways for you both to stay connected.

However, let me answer your direct question.

When you're having sex, there are a number of biological, emotional, mental, and/or psychological things going on than just the physical. For one, if your brain was imaged using a PET or fMRI machine (they measure blood flow and neuron activity in the brain), you'd see...

...logical reasoning skills take a small vacation, aka the logical part of your brain shuts down to a degree. The lateral orbitofrontal cortex becomes less active during sex. It's responsible for reason, decision making, and value judgments along with reductions in fear and anxiety.

...there are multiple spatially remote brain regions that are active during sexual response. During orgasm, genital sensory cortex, motor areas, hypothalamus, thalamus, and substantia nigra all are on high during orgasms.

...during orgasm, the body releases a huge surge of dopamine. This isn't the only chemical released, but it is one of the largest - which is tied to pleasure, desire, and motivation.

...oxytocin is released too, which is considered a bonding hormone, which is secreted from the pituitary gland and released into the hypothalamus - it increases affection, promotes closeness.

...prolactin is released also, which is responsible for that feeling of satisfaction, usually accompanies orgasm.

...as the pituitary gland is activated, the release of endorphins, oxytocin, and vasopressin promote pain reduction, intimacy, and bonding. This may help explain why things that might make us wince in a non-sexual situation, like smacking or hair-pulling, aren't as painful during sex and can even be pleasurable.

...in both men and women, the orgasm signals the parasympathetic nervous system to start down-regulating (or calming) the body. The prefrontal cortex, which was previously activated leading up to orgasm, also becomes down-regulated – and this is linked to increased levels of oxytocin to facilitate attachment.

...the brain also churns out serotonin after an orgasm. This hormone is known to promote good mood and relaxation. In some people, serotonin can also lead to drowsiness and the desire to curl up for a nap.

...in women, oxytocin tends to continue to be released after orgasm, which may explain the motivation for post-sex cuddling, their brains react somewhat differently post-orgasm than men.

So, to be very clear about the answer -- there are many benefits, reasons, and underlying biology, neural-chemistry, and changes that are happening. All the physical activity is very healthy exercise, studies have proven that sex can be a very vigorous and healthy exercise -- exercise several times a week helps your brain and body in several different ways. Additionally, sex can help you and your partner feel closer, connected, bonded, and in step based on the release of those chemicals I'd stated above.