I feel kind of embarrassed, but last day I used my new bf's camera to take pictures and when viewing the pictures I took, I saw that he took pictures of our hot-looking neighbor when she was in her room changing, brushing her hair, etc. It was at night, the curtain in her room were not closed. He also took pictures of her underwears (bra and panties) hanging outside.

When I try to speak to him about it, he either say it is for his friends, that I am making a drama out of nothing, that I am jealous, etc. So I said nothing and kind of forgot the incident. I feel like he is feeling embarrassed so he doesn't want to tell the truth.

Honestly, I don't know how to react. I feel it is strongly inapropriate for a man in his 30s, I could understand if he was a teenager, but he's not. I feel like I am losing interest in my boyfriend because of this. Like I am less attracted to him.

Did someone experienced that before? Am I overreacting?

Please help!

Over-reacting? No. I would have dumped him yesterday.

'... my new bf's camera... ' Is the camera new or the boyfriend?

He's your boyfriend, not your husband. If he's new, that counts for less than if he's not new. If you have children together, that counts a lot. If you own a house and or business together, that counts for something...
But bottom line, there is no Handbook of Rules for relationships straying into flirting, peeping, having lunch, texting, crying on shoulders, or any of the million other ways people stray off the straight and narrow.
If it bothers you, then that's that! If you feel less attracted to him, and can't work it out by talking, then consider breaking up. I'll just say that men seem to be genetically programmed to gawk, to revert to teenage behavior, to want to show each other what they saw. Two priests talking can't even keep their eyes off someone attractive walking by.

I might say something to her about how visible she is to the world.

The boyfriend is new, not the camera ;)

So you dumped the guy of many years? The one with the lists about 'finding a girlfriend' and who wouldn't share his car?

You weren't over reacting, what he did was inappropriate, and so was the reason he gave for doing it. To show his friends. Of course you are losing attraction for him, and well you should.

Don't ignore that very real red flag about his behavior or thinking (even if this neighbor was doing this on purpose), or he was making excuses about his purpose for taking pictures in the first place.

New boyfriend? YEP!

Here's what's bothering me a little... exactly a year ago, you were upset at lists your boyfriend (the old one) had written, and we all got into the topic of snooping.
You mention that you borrowed this new bf's camera to take pictures, and 'found' his pictures on it.
So what do we think? I know that I wonder just how much you trust any man, and just how much you happen to see things of theirs by chance, and how much by snooping.
What if these pictures were taken long ago? What if they really were taken because some other guy at work said 'so you have a hot neighbor, can you take a picture?' What if they were all taken during a short time frame, just once? You don't say how many there were.

Anyway, I'm in the 'harmless until proven otherwise' camp. We know nothing about your boyfriend, and very little about you. It needs to be in context.

You haven't over-reacted. I think you should be glad you didn't find pictures of yourself in a compromising position/situation.

I agree with making him a new 'ex' and walking away. I certainly wouldn't trust him. If he thinks it is acceptable to take pictures of his neighbor and her belongings (even if he doesn't share them) without any form of permission given on her part, I would be afraid that he would decide being in a relationship gives him implied permission to take pictures of me and do what he wants with them. Not a chance I would want to take.