Should I tell him how I feel or just forget about it?

I've been in a relationship over the last four months and I'm very happy in it and there's been a few bumps so far but nothing even remotely serious. After our first date we spent the next three days together because we both said we felt there was something real there and we even agreed to no sex until we made it official. After those first four days I deleted all the dating/hookup apps on my phone and hook up buddies' numbers. He kept pestering me to delete one hookup buddy's number who kept texting me the first week we were dating and so I did. He kept talking to me like I was the only one in his life and I felt the same way.

Then two months into the relationship he revealed to me he dated another guy the first couple of weeks we were together and it bothered me so much even though he kept saying it wasn't a big deal because we weren't "official" yet so I just lied and said it didn't bother and moved on. The third weekend we were together we had sex and made it official, that same night he went out to multiple gay clubs with a visiting friend and I didn't go because I had to work early the next morning and I didn't think anything of it. Now this past weekend I found a picture of him, his friend and some unknown guy from that night and I asked him who the third guy was and he brushed it off and was being very vague about it. Then I started talking to him last night about that night he went there and he was saying things like "We had only been dating a few weeks" and "I guess I was still in that mindset of being single" and now it's really really bothering me that he said that especially since that was the same night we made our relationship official. I'm going to tell him tonight that I want him to stop saying that he felt strongly about me since the beginning because I feel like if he really did he wouldn't have continued dating other people and he would've deleted that dating app on his phone (which he did not until a week after we made our relationship official). I don't know why this is bothering me because we have a great relationship but when I start to think about those things it takes away the genuineness of our early relationship and I get down about it cause I feel like he wasn't being as serious as I was in the beginning.

Am I overreacting? One of the best things about our relationship is we have great communication and always tell each other when something is bothering us so we can resolve it.