The biggest thing that happened to me in the past few years was meeting my husband, and getting married. I never had a lot of boyfriends, and went from being very single to being in a serious relationship within a space of two weeks. It didn't let up from there. Meanwhile I found my life changing in other ways. Rules that I had tried to live by were relaxed. Things were more hectic. Hobbies were abandoned.
I know that I have changed a lot. I believe that my husband has changed a lot as well. I see the changes, although I didn't know him before I started dating him, so my opinion is suspect.
One challenge that we face and that I imagine is common to face when you start a relationship is how to live your values. I care about conservation. I was working in the field when I met my husband. But I don't think that he had ever though seriously about conservation. He has other pet issues, which I had also not considered.
As we have grown closer to each other, we have both started adopting part of each others' pet issues. I have become more frugal. He has become more interested in conservation. He warns me against becoming a fanatic when I state that I don't want to buy any cheap plastic toys for our future progeny. But he is often the one to point out how we can cut down on driving to save energy.