How can i tell if my bf has gone back to using herion

[43ma_ms]

My boyfriend of a year i think he might be back on herion .. he sweats a lot and i mean a lot hes eyes are pinned and hes voice changes from a normal tone ..he sleeps a lot through the day and when he comes to bed hes asleep again with shouting and twitching and jurking movements , he is on methadone and has been for 12 years ..everytime i confront him he gets defensive and walks out , im at the end of my thether some days he looks normal and sometimes hes sweatin and tryin to clean up and i think this is hes disguse so i dont get on to him ..oh and he dosent eat meals he only eats cearal and choclate n custard all sweet stuff .. please can someone shed some light please hes put me through so much in a short space of time , one day he is all romantic and loving and the next day nothing not a hello .. would this be due to heroin .

[Knifeguy]

If he's on methadone it can cause similar symptoms to any other opiate. Support him in his journey to get clean.  Until he is clean from opiates for months he could be unstable, depressed, moody, not hungry. I've taken methadone and it made me feel like all that and took months to feel myself after stoping... and still went back to using. Addiction never goes away, and who he hangs out with has a lot to do with his success.