Monomers are broken up through hydrolysis reactions. This is when the monomers break and are "capped" with a hydrogen or a hydroxyl (if not, then such molecules can do damage to the body). This process is aided by enzymes (proteins) which catalyze the reactions.
Spandex polymers are composed of three different monomers. Dialcohol monomers make up the rubbery, soft part of the polymer while diamine and diisocyanate monomers make up the rigid, hard part of the polymer. The three monomers of spandex therefore are dialcohol, diamine and diisocyanate.
The monomers of nucleic acids are nucleotides. Of polysaccharides: monosaccharides. Of polypeptides (the chains that make up proteins): amino acids. Lipids are macromolecules, but are not polymers, so they do not have monomers.
Monomers are the building blocks that are used to make polymers. Remember: mono = one, poly = many Monomers are like the links in a chain and polymers are like the chain. Many chain links (monomers) make up a whole chain (polymer)
If the macromolecule is a polymer, then yes it is made of monomers. There can be some irregular macromolecules that are not polymers and thus are not made of monomers, but they are special cases (e.g. carbon nanotubes with attached side groups).