Handfastings:Magickal marriage

The most basic gist of a handfasting ceremony is thus: you begin by blessing the space. Then you call on spirit to empower the space. Calling what is sacred to the couple to the space Gods/Goddess or the power of nature, trees, the moon, to bless and empower the joining. Then you bind them together (for however long they have decided). This joining is usually two hands.The bindings can be made of anything but witches tend to use their measures. This adds power and meaning but can cause problems too.The act of binding makes it harder for the couple to reach out to other people, makes it far more difficult to leave a relationship that has naturally ended, and can have other side effects.
 At this point they make their vows, "to all that is sacred I swear by the sacred earth of my body, the Moon above and the light within to love, honour and respect you...." This kind of oath and promise within a circle means breaking them has serious consequences. If you cheat on your partner or break these vows you are likely to upset more than just your partner. You have called the Gods and spirits their and oaths are important to them.
Next in the ceremony people usually drink from a blessed cup (mead/wine/ale) and share it around everyone there. You can then remove the binding as the symbol has taken hold.
As usual you then thank all you called into the circle and release the circle. A handfasting sounds great but I have seen people who would have been happier and healthier apart "stuck" together longer than they would have been but for the magickal binding. I have refused to do some handfastings because I was not happy that this kind of bind was appropriate or a good idea. A handfasting is super personal, much more so than any other kind of wedding I have seen. It binds the magick, karma and energy of two people and families and is not easy to undo. I think it is the most serious and joyous way you can show your love and commitment for someone. You call on all you hold sacred to bless and bind your lives together. That doesn't mean it always works. Yet the deep raw emotional power of such a service should never be under estimated. 
This spiritual handcuffing to another person makes "legal" marriage look tame. I have seen and know un-handfasting services too. Magickal divorce is sometimes the hardest and most painful of them all.
"Jumping the broom" is not "marriage lite". It is the most profound way of connecting with someone other than the Great Rite.