Bf started using condom

My boyfriend and I use to have sex all the time and always did it raw. I was on birth control. Lately we only have sex once a week and now he has decided he wants to use condoms. Maybe I'm crazy but to me sounds like something is up. We did have an incident where I did accidentally end up pregnant while on birth control. I lost it. After that we still kept on raw. Now all of a sudden he wants to take things slow and use condom? Sounds weird