please read this. i need any advice

i never make posts on here or anything. but i fucked up real bad. i didn’t cheat, but i lied to him and was dishonest. he wants to forgive me and move past it but i can’t. i talked to my ex (in cordial friendly ways) and that’s not the part that upset him, it’s that i lied about it for so long. i am completely over my ex in the fact that i no longer have romantic feelings for him. i’ve stated that many times to my ex and my boyfriend. my ex is also over me in the same way. most of the time i would give him advice for his new girls and he would help me with my boyfriend. we’d give eachother answers to homework and such. but our conversations were nothing more than like friends. but i lied to my boyfriend about it over and over again. he found out last night and was devastated. i know i am completely in the wrong. i know how badly i hurt him. i would take it all back if i could but i was in too deep. i wish i could go back and tell him so he didn’t have to find out from somebody else. he completely doesn’t trust me anymore, rightfully so. i never thought my conversations with my ex were anything to hide but i felt guilty about still having contact with him and that’s why i lied about it. but my boyfriend tells me he wants to forgive me and move forward and still wants to be with me. i want to be with him too. i didn’t cheat, i just lied. that is understandably a big deal to him. i don’t think i can forgive myself. he’s been nothing but perfect to me. he never deserved to be lied to like that. i want to work on it and gain his trust back but no matter what, i know deep down he couldn’t trust me again. i know i wouldn’t. i’m grateful that he cares about me enough to give me another chance but i’m scared i’ll fuck up again. i hurt him in ways i could never forgive myself for. i feel horrible. help