Feeling down :(?

Me and my ex-gf used to love each other on and off for 4 years, that's in highschool, i treated her good and really cared about her, except that she loved me way more than i did, so i hurt her by mistake a lot of times. Now that i matured, i was trying to talk to her again, because she's my first love and very special to me, i really care about her from all my heart, but to find that she's dating another guy its been a couple of months. So i couldn't do anything and i knew she wouldn't leave him for me because he makes her really happy ( i assume ), but she did mention that in the long run, she sees herself marrying me.

So the real question is, am i a good guy? because i really cared about her from all my heart, just didn't know how to show it, or am i a bad boyfriend that deserves to be hurt and don't deserve her?