Cheating or no?

So this may be a little long but I really am up in the air on what to think at this moment... we have a 2yr old son and a baby on the way and my mind is racing....

So the other day I was cleaning my house alongside my boyfriend. He came across a necklace and asked if it was mine - he knows I only ever wear one necklace that he got me. I told him no I had never seen it before. I proceeded to check with my girls to see if they had left it at my house one time when they were here but no one claimed it. I then got to thinking the spot where it was found had been previously cleaned a couple weeks prior (I know for a fact because I personally did it due to getting our living room back because my dog had puppies and they were now gone).

When no one claimed the necklace I got a bit anxious to know whose it was so I started to lurk his friends to see if anyone popped out to me I haven’t heard of - one person did. My plan was to follow her in social media (instagram) just to see if she had any pictures with that necklace - keep in mind nothing has been said to him yet because I want to get facts before hand. Call me crazy idc, been there before with the sneaking around social media with other broads with my ex.

Anyways, I requested to follow her, and then went to check Facebook too, but didn’t add her just lurked. They were friends on there, okay whatever that’s fine I didn’t think anything of it before. Within not even half hour of requesting to follow her in Instagram she instantly BLOCKED me. Which I found very weird. So I proceeded to check Facebook and sure enough, couldn’t find her anymore - she blocked me on there too? At this point it has me thinking something is up FOR SURE. Because why would she just randomly block me when she doesn’t know me? She definitely saw I was with him from pictures and stuff so that’s my thought as to why.

Fast forward a bit, I worked a evening shift came home and went right to sleep.

The next morning he questioned me about a tweet I made and then I said it was because of this and I asked him who this girl was and he at first told me he didn’t know and played dumb and so I said are you sure? And then he said oh it’s a girl I know from a while ago because (his friend) had a thing with her. MIND YOU; I only had one friend in common with her and that was him - none of his other friends whom I have on everything.

So we kind of got into it, I didn’t want to say anything just yet because I wasn’t 100% sure of anything. He kept denying denying and saying he wouldn’t do that because he has a family with me etc and I’m like well it hasn’t stopped people before. And she has a kid and boyfriend too so quite honestly you never know.

So now it’s been a couple days and things in the house are obviously not the best, we aren’t even talking and it’s just kinda.. awkward.

Don’t get me wrong, I will own up and apologize if I am wrong about him not being faithful but until then I’m standing my ground. I just don’t know what to think from this because right now it’s not adding up at all....

Helpppp.

EDIT; I forgot to mention that he has been weird with his phone lately too. In the sense of when I ask to use it for a quick call or to look at something quick when I don’t have mine around or it’s almost dead, he’ll check it before giving it to me or want to dial the number himself when i want to call someone

Also, the necklace isn’t anyone’s who’s bought a puppy because the pups went to family and close friends.