Honestly, I've got two guesses on this.
1) He has some form of religious objection to contraceptives, which means either you've been chaste or very lucky (I'm guessing the former if this is the case).
2) He believes only women who sleep around go on the pill.
Not that it really matters because it's your body, so you get to take whatever medication you want. If he's worth keeping, he'll accept your choice.
3) He may be thinking about having kids already.
Depends how old are you, how long term your relationship is, but he might be thinking, that not using condoms any more is a decision that can be made instantly, and he has a say in it, while getting off the pill might not be that fast, and 100% not his decision.
True, but I was trying to err on the side of him being misinformed or having personal objections, not being a total @$$hole.
Ask him why....
Reason 2 - WHAT? People actually think this?... Holy Moly.
Actually, that's the first I ever heard about women being on the pill are promiscuous...
I hear it rarely, but juuuuust often enough that it may be a possibility.
Haha I guess I need to get out more!
#2 - never heard the pill one either, however I have heard that's the consensus if woman have condoms.
Question for the asker, is your long term relationship exclusive? I ask because after a YEAR of dating my boyfriend, condoms were getting expensive and we had a few slip ups. I was worried about getting pregnant so I told him I would get on birth control and he freaked out.
Turns out, for him, getting on birth control was what alerted him we were IN a serious relationship. When we finally talked about it, he explained even though him and I were only seeing each other, that kind of decision was a very 'committed couple' thing to do and technically we had never had "the talk". For him, me deciding to get on the pill was his interpretation of 'the commitment talk" and it set off an alarm as if I was speaking in code to tell him, "hey if you didn't know we're in a committed relationship." He wasn't afraid of having that conversation, it was more he felt I was being sneaky. Kind of like planning a wedding without a proposal. Odd, yes, but I understood his point of view.
I don't know the ins and outs of your relationship, but just in case it's similar I thought I'd share.