why is my ex doing this to us

[crystalflower]

hi me and my ex broke up after ten years and got a 8 year old child together we was having problems with my daughter and i was pushing everyone away my ex thought i didnt want him he used to say he was going to jump of a bridge .and he would say he hoped he would die before me cause he couldnt live without me .he just wanted to spend time with me but i couldnt do it . he worked away all week but i used to act like i didnt want him or the kids around me .he got me to get a job then two weeks later he walked out of hes so after a couple of weeks i asked him to go back to his mums he left a couple of weeks later . but we didnt finish we carried on as normal for 7 weeks then he rung me and said he been out and up all night i was mad .then a few days later he ended it in a text i was heart broken .he got back in with a friend who smokes pot and drinks alot he started to see his sister .But then he kept coming back to me sleeping with me saying nothing was going on with her then 3 months later he had spent a couple of nights with me then hes mum told me he was with her . he as changed so much his behaviour attitude the way he as treat me and the kids . he made his mum ill with it all she said its another side to her son that she didnt knew exsisted.i think hes on some kind of drugs he gained weight had coldsores boils on his bum and face rashes he had the shakes round me he came up once we had slept togehter he thought i was going through his pants he was digging deep in is pants then said dont tell anyone iv been ere but then drops me of at work .he told me to move on as he as i said yes you moved on with first person who showed you attension he couldnt answer back then he said i f---ed his head up .hes had are son to lie to me and keep secrets .once i went to get our son back he was talking slow and was spaced out i said to him your f---ed he said i know and me daughter said you on drugs he bit at us then went all calm i let him him come up a couple times to se our son .he gave our son a kiss at the door then our son walked away then me and him was stood at door then he said i miss you i didnt reply then he said i miss you ya know so i shouted our son back then he came the week after he wouldnt sit in living room with our son he sat in kitchen watching me and coming on to me is pupils was big he was nice asking if id been out and that i looked in his eyes there was nothing there he was empty then third time he did it again thinking he can crab at me and touch me so i said its not fare he agreed its not fare on me and i said why he couldnt answer me so now iv cut all contact with him hes sees our son at his mums .he told me he pleasures him self all the time thinking of me and that and he only feels that way with me .so i would be grateful for any help