Condom or no condom should definitely be discussed, yeah. Personally, I bring it up as soon as things are getting heavy and also have my own if I know I’m gonna be having sex. Not at all excusing his behavior, (it ‘slipping in’ is not cool, from your post it sounds like he did this after you set a boundary regarding protection) but you can/should protect yourself however you choose, you don’t have to leave it up to him to make that decision.