let’s see here…
-had (presumably) unprotected sex while you guys were on break, didn’t warn you about this, instead tried to lie and get away with it. doesn’t matter if it’s “technically cheating” or not, it’s inconsiderate at best, and putting your health at risk
-does, in fact, spread an STI to you
step back and try to look at it from a more objective, less emotional view. this relationship isn’t perfect at all. (in fact, no relationship is.) just because you guys had some great “honeymoon periods” doesn’t mean this is worth holding onto long term. most relationships have an “expiration date” if you will, and yours has come.
he is an immature jerk. you said it yourself, you’re the one distraught over this breakup and he barely seems to care. so WHY BOTHER WITH HIM? if you get back together it’s not ever going to go back to the “good times”. it might be good for a few months and then it will be worse than ever. he will probably eventually cheat on you but for real this time, since it seems he’d be “stuck” in a relationship again that he didn’t really care about before. dude… what if you catch chlamydia TWICE from the same stupid idiot boyfriend? i can’t imagine
channel your inner “coldhearted b*tch” and completely cut off contact with him. no trifling with any “we’re on a break” “we’re just friends sort of” whatever. delete him on facebook, block his number, if he tries to contact you in any way, do not respond. this is the fastest track to getting over him. which needs to happen, and it WILL happen, don’t worry.