Will my boyfriend break up with me?

The only way to get out of it is by telling the truth. If your time with this guy meant nothing to you then tell him that. tell him that it just wasn't important enough for you to even mention it. So he shouldn't worry. you would care less about that guy and if you can go back and change things you wouldn't cause you just don't care about him his just a friend? but if it meant something then tell him the truth and maybe it would be best for you two to brake up.

What TheSunGod said.
He should understand that even though you are in a relationship with him, you guys aren't married or anything, and it's not like you did anything on the ride with that other guy, what's to be unhappy for?
I have never even begun to mind my ex's when they were chilling with friends and got drove home or whatnot. The comparison isn't very even, but still, it's pretty obvious your boyfriend is uptight about this. If he feels betrayed. it's immature of him. You really don't need to say sorry. Tell him that you are innocent, have done nothing wrong, and that you shouldn't deserve to be the target of his anger.
I don't think he'll dump you. But he might become more suspicious.
And don't ever hide things like that again. unless his temper is that strong. just try to avoid "embarrassing" situations I guess if your boyfriend is so tense about these kinds of things.

This whole situation is kind of ridiculous. You went for a ride with some guy. So what? Right? Normally I would say that he needs to grow up and learn that in a relationship the road is full of bumps. And although this fact is very true, Nutz76 makes an excellent point. It is just too suspicious that you kept an innocent ride in a car with another guy a secret. Whether anything else happened during that drive or not is largely irrelevant. The key is in how it's interpreted. Right now, your boyfriend's perspective on the situation leaves him well within his rights to be suspicious although I don't think dumping you right off the bat is the right thing to do nor do I believe that is what he will ultimately do. Still, now is not the time to breathe easy. You need to TALK to him, tell him the truth no matter WHAT it is. And you need to make sure that there is no doubt in his mind that you are still 100% his. And next time you do something that could be seen the wrong way, talk to your boyfriend as soon as possible or beforehand. If you had done this regarding the drive in the car, I think he would have been totally ok with it. Keep that in mind.

Pray first. Let God have authority. If you have broken his trust, you need to talk with him. Be honest. Let him know how you feel, concisely. If you take more than two sentences, he may not be listening to the third. Three questions to address are: Why did you go for a ride with the other guy? Why didn't you tell him? Would you understand him taking the worst possible option for vengeance?
The key is to earn his trust back. It will take time and investment on both parts. Let him know you care about him. Ask him how he feels, listen, and validate his feelings - they are his. Then respond in love, not desperation. In simple terms, love him.

He feels betrayed because you hid something from him. It's not a stretch to imagine you were cheating and are trying to hide it. If you were honest with him from the start this wouldn't have happened. My gut instinct is that there's more to it than an innocent ride, otherwise you wouldn't have made an issue of it enough to warrant hiding it. (at least that's what his instincts will be telling him)

Ask yourself if there isn't more to the situation that would have brought this on? Has he been jealous of you with other guys? Have you given off any unintentional subconscious cues that you may have interest in other guys?

tell him he truth.

does "go for a drive" mean something besides what it actually sounds like? Because if not, it sounds like he needs to chill out! Now, the fact that you never told him may mean you - on some level - felt guilty for whatever reason, and if that's the case it needs to be addressed. but please, if he's going to break up a three year relationship because you hung out with another guy a). there are MUCH deeper issues here, or b.) you're better off w/o him. or both!

*good luck!*
www.whywasidissed.com

no if he loves you he won't as you only went for a drive its not like you cheated but you have to ask yourself why you kept it from him and explain to him why