It's hard when this happens Tara. A lot of time I see people--women--you are good friends with while they are single, then they get a boyfriend and BAM your friendship is on hold or goes by the wayside because all their time and energy is now spent on someone they love. Sometimes they come back to you, sometimes they don't. The friendship is over and really no one as at fault, yet it's still just over.
Other times someone will hurt someone's feelings and the offended party doesn't speak up or say anything and you as the offender don't know! You don't know how to apologize or that you have to apologize because you aren't even sure what happened.
This is something I do know, that friends, like marriage, your job, and children, take work and dedication. To simply say a friend is always a friend no matter what is not true. You have to work at a friendship, be a part of a friendship and not just expect them to be there for you whenever or vice versa. If you are a friend who's not willing to do that, or your friend is not willing to do that for you, then the friendship suffers and fails.
If the words, "I'm sorry if something I said or did hurt you" don't get you back into someone's good graces then perhaps it is a friendship that is not meant to be.