Ex boyfriend and his bestfriend

I’m a tad bit confused as to what I should do .. now here’s the sticky situation long story short me and my ex still live together , we don’t talk he has a new girlfriend already but I’ve just been chilling not gonna lie I am hurt like hell but I’ll be okay now here at the apartment is also his bestfriend .. ever since I came back he’s been tryna get me to go out and do little things with him like go to church or having a smoke session with him or just asking about something in my room 🙄 now last night he messaged me “ come in here I can keep you company if you want “ in my head i automatically said wtf this nigga buggin and I said it would be weird because if my ex walked by and seen us in the room together idk what would happen and so I’m like I’ll smoke with you so I roll up and then walk over to his room now I’m sitting on the floor next to the door wide open and my ex walks by and double looks then walks by again and goes downstairs .. so 6 am my Ex is getting ready for work and here comes his friend Inbox me “ you gonna come lay in here with me or what “ and I’m so confused because I just woke up and wasn’t expecting that so I said omg , I rolled up and asked him if he wanted to smoke ( usually that helps get people back to the right state of mind ) and he said yes so it’s 6:30 Am and we smoking , we finish the blunt and he still sitting here so I’m waiting for him to leave and I sort of get impatient and politely asked him if he could go back to his room and he wouldn’t move so I tried to help him up and he kissed me .. what should I do !

PS - HES ALSO IN A RELATIONSHIP WITH HIS BABYMOMMA BUT WHEN I ASKED HIM WASNT HE IN A RELATIONSHIP HE SAID IT WAS COMPLICATED AND THAT HE WAS WITH HER SO HE DIDNT HAVE TO PAY CHILD SUPPORT.