Can somebody please define a "healthy" sex life?

Safe, happy, and with pregnancy dealt with in the manner you prefer. It's healthy to have the type of sex you want to have, and to have that sex safely, and to enjoy that sex. That's all, there's no requirements for who you're banging or how often or how. It's just that you do what you want, protect yourself from disease and unwanted pregnancy, and that you are actually enjoying what you do.

Whether that's a session of whips and chains every week between spouses, monthly missionary with someone whose name you don't know, or something involving yodeling, dental dams, and 3 coworkers....the only common link is that you're sexually satisfied and safe.

A 'healthy sex life' is one that is mutually satisfying to you and your partner. If you are single, then it would just apply to you (regardless of what casual partners you may have).

If it makes you happy, isn't degrading, and doesn't hurt others or yourself, it's "healthy".

And if you think sleeping with multiple partners isn't degrading and possibly hurtful to yourself or an eventual spouse, you're wrong.

My take and way I think of it when I hear health sex life is regular and enjoyable sex with a partner your with.

Creating and keeping a bond together?

I think it's in regard to whoever you're having sex with at that time.