i'm so sorry you are going through this. i know a tiny bit of how you feel. not knowing if you should wait, and not thinking that you will be able to love anyone else again. but this simply isn't true. im trying to learn this right now.
i recently lost my bf because i was kissed by another guy when i was drunk so i would be a hypocrit if i said " why do you care about this guy, he cheated on you" because i am trying so hard to get my ex back... but in all honesty, why is out having sex with other people while you were taking care of your dad? he should have been on the phone with you every day, or he should've been by your side or something. i think you deserve better personally. if he's your boyfriend, he should only want to be having sex with you, no one else. if you stick by his side, and he does end up falling in love with this girl or whatever, then you'll have to take even more bad news. then you'll feel 10 times worse. you can stop more pain from coming if you maybe step away from the situation for a while, and take time to yourself. don't start dating anyone or anything, just take time for you. and if he does come back even after he's been living with this girl, etc. then you guys can talk again. i feel as though you will have a lot of trouble gaining back his trust and everything...and deep down, i do feel like you deserve better. find soemone that lives near you and that wouldn't have sex with anybody but you. that is just how i feel.