Please kind od complicated and i am so stressed right now il answer your questions if you answer mine?

my bf of a year dumped me a couple of weeks ago and just got back together today i got told by another mate that he was datin or seeing another girl in the friendship group and that he dumped me to get with ehr and then dumped her yesterday after a week i asked him about it and he said that it wasnt anything serious by i think its would of been to soon to get in something a day after he dumped me..... how would you feel what would you do he sayd he loves me and everything and i feel the same way yet i cant understand if he loved me he dumped me(there was reasons) then get with another chick so im not sure i want to be with him