Please, help me with this guilt I feel.

Last summer, in August, I got engaged to this beautiful boy named A. I was very much in love and I was very close to him. We were together for 3 months where in half of the relation he treated me a "badly" as he was very distracted, but then he changed and became very nice to me. Always in the summer When I didn't see myself with him I went out with my friends (who I no longer have) where there was this guy, G., for whom I had a crazy crush for years, which obviously no longer existed being with A. In November speaking, it turns out that G was in love with me. Without knowing anything, A. wanted a break for no reason. I take this as an excuse to leave A. He changes his mind but I was convinced of what I was doing. I get engaged with G and among many lows we reach today: a year has passed. A month after we broke up A. writes to me and asks to remain friends because having been little together it was nothing special ... In this year, among the many quarrels I have often thought of A. and especially in this period where feelings of guilt assail me and kill me. Now after a year G, he has given me so much and I feel guilty for destroying everything .. especially the relationship I have with his family which is beautiful and they have always treated me like a daughter. and then there are future projects such as living together etc .. On the other hand I am afraid to hear again A. because I think he has gone on now so I would be too selfish. I do not know what to do. Please help.