Need help and advice on my marriage of 14 year

hello first of all please bare with me this is my first time on a help forum. but im hoping any one can help me as i can not cope feeling the way i do any more and its driving me mad. me and my husband have been together for 14 years i got with him when i was 14 years of age we have 3 amazingly beautiful children my eldest 6 my middle 3 and my little boy who has recently turned 1 years old. just before Christmas day i found out my husband was having an affair with a women at work for several months well he says it was only a month started in november but looking on his call/message history it was alot longer then that please dont think im a snooper im far from it he has all the privacy he could want or did have i didnt know passwords for any thing i never went through his phone or even knew how much he got paid or his bank details as i trusted him 100% so never questioned him or felt the need to. this is where my problem lies i was sexually abused as a child for many years i didnt and dont trust any one i find it very hard but me and my husband grew up together our mums are best friends and have been since they was 12 year old so its not like i didnt know him and a few year of us being together i finally felt at ease i felt safe and secure and learned to put my past to the back of my head i could sleep my husband became my blanket if that makes sense my problem is my husband thinks as its the first time he says of having an affair he is pretending it is all ok and fine but its not far from it my past has come back like a house falling down on top of me and i dont understand why why am i thinking of my past why has it come back. my abuser was my grandad i loved him dearly and trusted him and i thought up until a certain age that it was normal but as i got older i realised it wasnt and what he said and did was not love. i am so so sorry for this post but my mind is all over the places.
i do understand the excitement of some one wanting you the attention and it is nice for some one else to find you attractive it makes you feel good makes you feel sexy and wanted but he took it to far he didn't say no he disappeared for a whole night and this is very out of character for him as he as never ever done this before i found Durex in his work bag and he claims that they was for us but im on coil so we haven't used them for a while and the sex did stop for 2 month even though we did have a very active sex life. the funny thing is i should have known my husband came up to me apologizing of the lack of sex and that it was down to stress at work but he had a love bite on his neck when we had this conversation and i can remember questioning him about it and he said that i had done it the other night even though he just came up and apologized for our none sex life over the past few month all this was a few month before i found out then he stsrted buying me things and being nice helping round the house i nearly died when he said we was going out never in 14 years had he taken me out any where i was so excited but still hurting from him going out a few night before and not coming home until 5am. oh my head hurts right how do i get past this trust now i have gone from 100% to -100000000% i dont know if i can carry on to be honest i am sorry for my long winded scattered story of my life i just need some advice. and thank you for taking the time to read