A bit of a touchy subject but I need advice

My nearly a year boyfriend I haven't had sex with him for nearly 6 months due to him being abused by he's girlfriend..when we first met we was quite often like when I see him we would do it so 3 times a weeks 4 months into the relationship he stopped all together I was always wondering why I asked him over the months but got no answers its only recently literally a month ago apparently he was abused but I don't know wether to believe him or not I feel very bad that I'm doubting him but their is my reasons first he was like I'm not a sex driven person like he said he doesn't "need it" he's 19 by the way and I'm 20 and I'm sorry if anyone out their has been abused and is in this situation just know your strong and you will over come it.. I don't know if he's telling me the truth what are the clear or maybe tell tell signs that maybe he was?..like I feel abit like a slag lol when I try hint at him for sex he loves me a lot apparently but like

Refuses sex every time what's going on or is it that do you think?

Thankyou for taking the time to answer hugs x