how to fix a relationship where you cheated and feel the guilt

this is my first post here I don’t know if giving too much context is the right thing to do but it also gets it off my chest

this girl loves me so much and I love her so much too, she’s so beautiful and so nice to me. we both have done so much for each other, it’s been a couple of months since we’re together. last night I texted another girl on ig in a way I shouldn’t have, idk what I was thinking of achieving with that now that I look it at it was so stupid of me to do so. I feel miserable.

but I made my mistake and I owned upto it, i want to fix our relationship she told me after so much talking that yk we can try again it was all a stupid fucking decision on my end and the guilt is killing me.

how do I get over the guilt and be better for her and moreover, how do I fix us.