Relationships

I would like to muse for a while (hopefully intelligently) on relationships. A freind of mine, who hopefully won't be offended by this, is having a few issues with her relationship. She is very obviously keen to be in a good relationship, which I can completely relate too. At some stage she also hopes to have children, which some days I can also relate too.

Where do you draw the line? When are you able to say "This is good enough" Should you have to compromise like that? If you are asking that question, does that mean it isn't good enough? For me, I have asked my self that question in a relationship twice, and each time I was so disgusted at myself, that with in days/weeks I had ended the relationships. I get the feeling that a relation of mine has far more objectively discussed "good enough" with herself more than once and decided that yes it is. Am I to awful for not being able to understand this? What happens if one day you turn around and decide that it's not? Is it a good way to be in a relationship?

Obviously I am desperately trying to sort out my head here and I think the main reason I am having so much trouble is that, being a very black and white thinker, and this being a rather gray area of life, it will probable never fit well with me. Sounds like I'm giving up doesn't it? I'm not I promise, I'll revisit this topic, after a few drinks and some discussion with some people.