trouble in paradise

so we were having sex right? well we heard someone outside his room so we stopped and put the blankets over us and i thought they went upstairs so i told gim to face toward me and i was just going to tell him i love him and before he even rolls all the way over his mom throws open the door and then slams it shut so fast. i think she saw i wasnt wearing a dhirt but we werent even having sex when it happened i just wanted to tell him i loved him. anyway he gets so upset and angry (which i dont blame him) and i try to calm him down and he says “you act like it isnt a big deal because you dont have to hear about it” and im like thinking i dont even want t come here for like a month now because im so embarrassed. i didnt say that though. instead i just said i know its a big deal and i asked if he was mad at me and he said no. well then like 20 min later he says something about giving him head bc we didnt finish but he’s still in a bad mood so he is on twitter and stuff so i start just to get him hard and ask if he’s going to put his phone down and then he got pissed. he said “never mind im going to bed” and he just was ignoring me and being mean. he knows i dont like him on his phone when i give him head (he says he likes to look at pics of me but i know there is also porn on his phone so idk what he is exactly looking at, and if not looking at nudes he’s literally on soocial media? while im giving him head? (this stopped he’s only done it a couple times. it didnt bother me at first)). anywway he’s pissed right? well i asked why and he saidbecause i’m acting like an idiot. and i said “why? go abead explain” and he just wouldnt say anything and i eventually asked if he wanted me to go home and he said “sure go ahead” because he didnt want me to but he thinks i want to. i asked why he was mad at me and he wouldnt answer or say anything and he just keeps saying to let him go to bed. I just dont know what i did wrong. (ps he’s bipolar and isnt on any medication so he cant really control his moods sometimes. he struggles with it.) and i know some of yall are gonna be like “oh leave him” but we NEVER argue, and this isnt even an argument i just dont know how to do anything about his mood or whats wrong. he’s honestly the sweetest boy to me and the closest person to me. he does so many things that just make me so happy that i cry. i guess i just needed to talk about it but any advice on what to do would be great. we’ve been together for 16 months i’m not breaking up with him bc he’s upset his mom walked in on us so please dont suggest that.