[Solved] my son feels abandoned

hi im joanne i split from my sons dad 4 yr ago he used to work 6 nights a wk and so you can emagine he dident really get much father son bonding time,i have 3 sons and 1 daughter by him my son is now nearlly 12 so he was only 8 when we split and we did have it hard he letf ME for another woman not the kids me, this is what i have always kept telling them when they asked it was not there fault it was us as adults, well from then on we had been kicked out ov our family home which i could not afford to buy his shaire of the house so we could stay i felt so bad not being in a possition to do that for my children, so my children went through being thrown out ov our home moving from a 4 bed house to a 3 bed so all 3 boys are in the same room my oldest is now 16,they saw there dad all the time at first then he started to let them down ,turning up very late,so late they couldent go with him, he stole our dog because i wouldent give him back a computer, the kids used for ther home work. he then started parading the woman he left me for around with them and they got confussed cus all they wanted was time with dad on there own,we tried to explain this to him but things dident change. now we are settled in our home all 3 boys fight for there own space which we all find hard,i have had constant battles with my 12 yr old im trying to reasure him all the time even going to the extreme where i buy xmas pressies for them and say there from there dad because i dont want them too feel bad about there dad i love them so much it breaks my heart when i think what he is doing to them, i give him every oppertunity to do things with them but he has his own hobbies which when its his weekend with them he wont ask them what they want to do they go too dog shows and the kids come back all deflated i wish he would see what he is doing it seems the kids fit in around him and not the other way around like it is with me.

my 12 old was at the shop with me the other wk and i mean it like 4 yrs on and my son went toilet and i said to him that i will wait for him which i did but not in the exact place where he said, when he turned around and found me his poor face was so emotional i said whats wrong he said i thought u left me here. i gave him a hug and said i would never do that i said i love you and we went home to continue the conversation where he said, that he thought i did the same as his dad done to him, as you can emagine we were both crying together.i said why dident you say anything before he said cus mummys heart was broken and i had lots of things to sort out like the house which did cause alot of stress for all ov us. if only i knew sooner i could have made things better. we are more open now but i cant forget that my son thought i would abandone him.

any one got any ideas apart from the usual things i can do i keep telling him i love him and try to reinforce im not going anywhere no matter what he does or says,.cus sometimes i think he pushes thing to see how fair things will go but i just say i love you and that you need to calm down.
when i talk to his dad he says that he is fine with him i dont know if its because he dont want to show his feeling.
there dad thinks things are like what they were when we were together but they aint he dont see what he has done to them just by walking out on them and not even telling them why he left.but he left that to me and as you can emagine i had to tell a little white lie to spaire there feelings. when my daughter askes him when he left, was it when we were in bed she said he just says to her shes to young to know the answer but i keep saying if she is old enough to ask the question then she should be old enough to listen to the answer