Today, our series By Design is taking on its most intimate project to date, looking at one of the most fundamental ways we design our lives... by day and by night.

Keeping the passion alive in a long term relationship is a problem many couples face. We still live in a culture that idolizes marriage, and monogamy... but many couples struggle to keep their monogamous relationships vital. And with people living longer than ever, the idea of only having sex with one person for 5 or 6 decades can be daunting.

Meanwhile, our culturally accepted ideas about sex and sexuality have undergone a seismic shift when it comes to many other issues.

So, today we're asking whether the time has come to rethink — and possibly re-design — monogamy for the 21st Century.

Dan Savage thinks so. He writes an internationally syndicated relationship and sex advice column called Savage Love. He is also host of a podcast called Savage Lovecast. And in 2010 he initiated the It Gets Better Project with his husband, Terry Miller.

Robin Rinaldi became something of an expert in non-monogamy, after her own, year-long experiment with re-designing her relationship. She wrote about her experiences in her book, "The Wild Oats Project: One Woman's Midlife Quest for Passion at Any Cost."

If you have an experience you can share, e-mail us or tweet us @thecurrentcbc, with #bydesigncbc.

This segment was produced by The Current's Kristin Nelson.