At the point when it starts to get neglected and the person does not care to keep it going, fresh and new.

NEVER! My Man and I have been together for over 20 years. We've been through mildly "lean" years, mostly after we had new babies and I was consumed with exhaustion, nursing and infant care. But, it always popped back and the sex was great again. (It was always great, just less frequent when we had babies, maybe 3 times a week instead of 6 to 12 times a week.)

There's no reason for one's sex life to go downhill.

I have no idea if there is a time when most people start to lose interest. I'm not old enough myself to have any experience with that. However, I do notice that if hubby and I haven't done anything for a few days, then we start to lose interest. This means coming back to it even if we don't particularly feel like it to get ourselves back on track. On average, we are about 10-14 times a week. If we haven't made time for each other, we start to get very snippy with each other and feel odd after about 3 days.

I hope never! We're a pretty active sexual couple and I hope it stays that way. I think it does take work though, like all aspects of a relationship.

when normal everyday affection and romance goes down, so does everything thing. like the previous poster said, it takes work to maintain a healthy relationship.

when you stop trying

10 months

When you're disconnected from the person you're trying to be intimate with.

If you and your partner are on the same page sexually and in tune with each other it shouldn't. I too have been with my husband 20 years and where it was great way back when it's even better now. The key I think is when you feel it is going that way to try something new and adventurous to get back on track.

I think if you keep it fresh and try new things it doesn't have to go down hill. There are nights that I'm tired but I try to find new things or sexy outfits and we usually do it 6 times a week and we have been together over 7 years and I work about 50 hours a week

Only when you give up.

when communication dwindles.

I've been married 24 years and it just keeps getting better and better.

Other people have talked about their relationships, and those can go bad at any time, from a week in to 30 years or more in. A relationship is a lot like a garden: you have to keep pulling the weeds, and watering/feeding if you want it to grow. And that care is required as long as the relationship exists.

But your partner is only half of the equation, at most. You also have to take care of YOU. At any time of life, but especially once you hit your 40s, staying active and healthy is VITAL to having a good sex life. I learned this a couple of years ago after a sports injury kept me from exercising for a few months. I found my sex drive plummeted and only came back after I started exercising regularly again. I've also found my libido drops off if I overeat, or eat unhealthy foods. The "garden of the self" has to be tended, too.