<human>: Summarize the given text in a few sentences.

I began dating my gf in high school.  We were best friends for a couple of years leading up to the relationship, so we knew each other well and everything started off smoothly.  Overall, I would say that our relationship has been steady and healthy.  However, lately I have had second thoughts for several reasons:

1. We hardly have any common interests.  I love sports, working out, and being active while she leads a sedentary lifestyle (leading to her gaining weight and me becoming less attracted to her).  She is quite extroverted while I have a social life, but I am certainly introverted.  Just a couple examples...we just don't have much in common.

2. Our sex life has gone from once a week, to once a month, to now once every 3-4 months.  I completely understand this is normal to a certain extent, but I want more and she makes me feel like I'm just using her any time I attempt to come on to her.

3. I originally fell in love with her and decided to take the next step into a relationship because she adored me and treated me extremely well.  I loved her personality and just her outlook on life; however, now I feel like she just does not care like she used to.  She denies this, but it's easy to tell.

I know I may not be a good person for saying this, but I'm not 100% attracted to her.  What attracted me to her was her attitude and wonderful personality.  But it just seems like her feelings for me just aren't the way they were before and I do not know how to proceed.  I love her, but I don't know what to do.
<bot>: Longtime girlfriend and I have nothing in common and her feelings towards me seem to be fading even though she denies it.  Love her but just don't know what to do.