Unable to Be Happy

Hi everyone,
I am new on here. I am 22. I have been diagnosed with severe depression and a bipolar disorder plus hypothyroidism. All this adds up to me being unable to be at peace physically ever.
Im stuck I am in a touch-wood simple loving relationship which was previously an abusive one. its so hard to explain he left me for an year i never stopped loving him he was going to marry someone else. In that period of loving him and being single i screwed up kissed a married guy when i was drunk. made out with a good buddy who broke my trust and clicked a picture.
Now me and my guy are back we dont talk about the past but it keeps irritating me. PLease someone help me get over the past. I feel so guilty for what i have done when i was single plus the shame of tht picture. but my guy will never accept it we are better off without it coming between us. I did tell him abit about it but he reacted so badly.
I love him. Is it ok to move on now without hiding anything hence forth.
I m so messed up depressed.