forgiving and forgetting ?!?!

so i had a bad experience with my ex he controlled me for 2 years and i was left with no friends it was hard as was so much jelasously in the relastionship . due to al the past problems i feel like i find it hard to forget and forgive things now . either that or its just the way i as a person am. i am now in a new relastionship for and he admits he made problems early on in our relationship we argues and kinda of aorted them out it wasnt anything major like cheating just things which hurt or upset me with girls or such things similar . the problem is i find it impossible to not think of these things some times even tho he admits he make a mistake and understand . i want to not remeber these things as when i do it upsets me which sometimes takes a toll on our relationship thank you for reading any help is much apprecaited .