My ex keeps hitting me up..

I've been broken up with my ex for about 2 years now but we've never really lost touch because we've always been good friends & we dated for 3 years & ive even known him since childhood. Just recently I found he is in a relationship but i still keep in contact with him, such as constantly texting & snapchatting. A couple of weeks back we met up to talk & hangout cause he said he missed me, we got really touchy & kissed but nothing more than that, it seems like he somewhat wants to get back with me & even told me he's contemplating breaking up with the girl he's with because he no longer feels the same about her; last night we were texting and he said he really wants me & misses me & wants to fuck..I've told him multiple times I wouldn't want too because I feel bad for the girl he's with but he keeps telling me he doesn't care about their relationship anymore, I still somewhat have feelings for him & really don't know that to do cause I have mixed emotions, I really want to just be with him & fuck the shit outta him cause dick is hella bomb but I also feel really bad for his girlfriend cause he's doing all of this behind her back, any advice on what I should do? Should I be feeling bad about this? Should I be considered a hoe or bad person ?