I know I haven't been married very long (3 weeks & 4 days, but who's counting...) but being married does feel different. I wasn't sure if it would since we've been dating for 4.5 years, living together for 3.5 years. We own our own house and were living like a married couple.
But I'm happy to say I have noticed a change, and Tom has noticed it too. I'm sure part of it is simply the "newlywed" phase we're in but I feel much closer to him. It sounds cheesy but I feel more secure & safe in our relationship. We have both noticed we have been nicer to each other and have been going out of our way to make the other person feel loved & appreciated.
I know for me, it's partly because this man is now my husband, and he comes #1 in my life. And I know I haven't been letting the little things annoy me as much because it's "forever" now. And I'd rather let the little things roll off my back instead of letting them annoy me for the rest of my life.
Either way, things are great between us. Being married is a wonderful feeling. :)