How do you forgive someone who has hurt you?

i've been going out with this guy for about 3 years and lately it feels like we're drifting apart. he's always out with his friends and it seems like we never have time for each other anymore because of that and anytime we do talk, we always argue. for new years, i was hoping that he'd be home so that we could at least count down together but instead he went to hang out with his friends from school (we go to different schools). he told me that i could text him despite the replies being slower. i did text him twice got one reply 4 hours later. and when i tried doing a countdown with him, i got no reply. i only got one happy new years text and that was it and he came home at 3:30 in the morning. i don't know what to do and i'm not sure how to forgive him and move on with my life. any suggestions???