What value/character should a relationship have for it to last long?

I think the big things, really, are trust and communication. Without either it just doesn't work overall and that's where I see a lot of relationships going wrong. If you have a problem with something the other person is doing, tell them. Talk to them about it. Because, really, if you keep it bottled inside then you start to resent them and that resentment just bubbles inside you until one day you're eventually going to explode out of nowhere. A bit of give and take is extremely important, too. I've seen way too many people fail just because they weren't flexible enough. Some people forget that you're in a relationship, which means that there are two people to consider, not just yourself, and people don't want to have to give something up. This can be something small just having to do with an item or something that leads to an argument (how many times have we all heard about that one?) or something big. Like my husband and I, right before we got married, went through the whole "jealousy" phase because he had been pushing me to start hanging out with people since I hadn't really been going out with friends or anything because I was working so much. So I started hanging out with friends from work, including a couple of guys, which made him mad. He didn't really want me hanging out with guys alone and I didn't want to give up that freedom because I've always hung out with lots of guys. In fact, that's how my hubby and I got together was that I was hanging out with him and his group of two other guy friends (with me being the only girl). So we sat down and talked about it and he was OK with me hanging out with my guy friends as long as he knew where we were going so that he wouldn't be worried and would know where to find me if he needed to, which was reasonable. So I think flexibility and compromise are definitely big ones, too.

Two things: communication and trust. It works for us very well. I am in a six-year relationship, and still going strong. We talk often. We just sit in a bench, just be together, and let things roll. We talk often of what we like and dislike. In that way, we won't be clueless of what annoys or makes each other happy. That also won't make the two of you strangers to one another. Trust is also important because it is not every day that you see what he or she does or thinks. You just have to have the faith. Also, small things have bigger impact. a simple foot massage or manicure / pedicure, or a cone of ice cream if the other is really depressed, or just a cuddle or tickle leaves lasting imprint in one's memory.

quite a lot of it i guess, but of course it should have selflessness. when you start counting what you are giving and what you are not getting back, i guess that is where you will feel and see the lacks and the missing elements you do not see in your relationship.