Weird or respectful ?

So I dated my ex for about 3 years we broke up and since then we’ve had a fwb relationship type of thing going on and since we never used condoms while together we had been doing it the same way (no condoms) this was the third time he canceled on me for a hook up which he always says yes and today he said “what if we’re sinning doing this?” So I was like okay? And he later said okay but maybe this time let’s use a condom just to be safe and I was like safe from what? Aren’t we only seeing each other and all he said was just in case?

do you guys thing he’s seeing other people and that’s what he means by using a condom.?