First and foremost, and something that makes us really just lucky... We have practically identical expectations of each other. Our thoughts on what is okay and isn't okay are the same in almost every instance. I think that being so like-minded is the main thing that has made our marriage easy.
Secondly, neither of us is irrational, and in the rare case that one of us does behave irrationally the other never responds irrationally. When conflict arises between the two of us, it is a one sided event. One person is mad at the other person. Neither of us brings anything up upon first thinking of it. We both sit on a subject for quite awhile and think it through very thoroughly, before we'll bring it up. I think this gives us a more realistic view of the situation at hand. When I think something through first, it lets me think about how I want the events to play out. Thinking alone first, may help me calm myself down, so as not to attack my husband and make him defensive. Many times this makes me realize that what I'm mad about is a little silly. I still bring up whatever I had been thinking about, even if I realize that I was being irrational, just to get it off my chest. Almost immediately after something is brought up, it is resolved. I think part of that goes back to point number one, we have similar ideas of what is wrong and right, so if one of us is mad, the other person totally understands and apologizes.
Neither of us is too proud, nor too stubborn to admit they are wrong or say they are sorry. I don't care how proud or stubborn you are with every other person in the world; with your spouse, there should always be room for submission, from both parties. Neither of us feels inferior or weaker for saying we're wrong or sorry. I think, if anything, it makes us respect each other more. Of course it's not always easy, and I may delay a minute or two, but once I realize that I am wrong, I admit it very soon after, as does he.
So these are just a few of the main things that I think make my marriage so successful and easy. I didn't write this to show off and say "look at how awesome we are," although we are pretty awesome, if I do say so myself;). I just think that in a society plagued with divorce, it's important for me to share what helps to keep my marriage a happy one. I know two and a half years isn't long, but most people who get married at the age that we married, have already divorced before the two year point, so I think we're doing pretty well. I have trouble believing that two people who have been as happy as we have been for these last two and half years will ever split up. I know anything can happen, but for now I'm sticking with saying that it won't happen to me;).