While I completly respect the other poster for her thoughtful opinion, I still have to disagree with him/her. I am 26 years old and my mom's mom recently died. While my grandma was alive, my mom was sad that she had to give up her life to help her own emotionally clinging mom (my grandma). However, now, my mom looks back and is glad that she was a good daughter.
You don't want to have regrets. Learn how to be happy by giving up your time for your mom. I'm doing that for mine now. Boyfriends/girlfriends may or may not stay. But, you only have one mom and you don't want to look back and have any regrets.
That said, I totally do agree, though, with the other poster in that you want your Mom to be able to be as independent as possible, as being too clingy will definitely sap the life out of both of you, and neither of you will be happy with each other.
So, in the final analysis, take some time to travel with your Mom and take some time to travel with your boyfriend and his friends. If he's a good boyfriend, he'll understand. And you don't have to travel a lot to exotic locations, maybe a great roadtrip across country that is more affordable or many an exotic place, but enough to not break your budget.
Compromise with them. You should be happy, and so should your mom, and boyfriend. However, for me, mom comes first. And you'll actually not be giving up living your own life by being with your mom. Rather, you will truly be living by knowing that you have spent some of the best years of your life being kind to your only mother.
Hope this helps.