There is nothing inevitable about relationships going downhill. Some relationships actually go uphill never to retreat. Interesting presumption, though. Very telling.

The relationship that goes uphill is the one you keep forever, so it's the last relationship you have.

Every relationship prior to that goes downhill, or the uphill one never would have started in the first place.

I so want to believe you. But everwhere I see the opposite. I do not know of a single relationship that has gone 'uphill'. They all deteriorate (and this is not just from personal experience). They deteriorate because the second you commit you either feel trapped or consumed - ie you want to leave and be free or you become obsessed or 'part' of the other person so much that it consumes your identity and you lose yourself (hence the immense heartache when it ends - you literally don't know who you are anymore).

I'm not trying to be negative nor am I deeply scarred and reacting to past experience (I don't think). Just what I see.

I'd leave the inevitable part out, but this is an interesting thought. I've noticed some couples who are completely wrong for each other and seem to need each other to fight with. They consider that to be the spark in their relationship. I couldn't live like that so that type of relationship would go downhill for me.

For someone your age it might look inevitable because you're just on the threshold of the time when folks tend to make permanent comitments, so there is a great deal of turnover. We have a lot of cultural forces working on us as well. We don't seem to value self-sacrifice any longer even though in the proper context and spirit it is probably more satisfying than living for ourselves. This is where some folks lose their way. They don't see the beauty in these voluntary commitments. We attack the idea of permanent relationships and then our political system subsidizes the results. It is good that we have choice and the marriages that survive in these circumstances are better for it, but let's not throw away the idea of a permanent relationship just because others are not successful.

These are half-formed thoughts but I have to get to work.

I see both. I think that may be the difference in out perspectives. My parents have the best marriage I have ever seen. They are in their 60's, so I guess it's possible that theirs may go downhill at this point, but it's highly unlikely. I'm in an uphill relationship with my wife. We've only been married 12 years, so time will tell, but I can't imagine this relationship falling apart. My previous relationships all went downhill, but that's because I got involved with the wrong person each time, and I wasn't ready myself either.

I've seen plenty of relationships fall apart. About half of all US marriages end in divorce, so that side certainly exists. Maybe I'm just lucky.