Is my Boyfriend a cheater?

I need advice ladies.

My partner and I have been together around 15 months, we have quite a unique history. We first met when my ex partner (let’s call him Jack) and I went 8 hours away to his home town. We were at an event and it’s there I met my current partner (call him Dave).

Now Jack and I had a rocky relationship, during this event he kept ignoring me and leaving me alone in a place and with people and that’s where I met Dave, he talked to me so I wouldn’t be so anxious and bought me a drink. He was super sweet and I felt something Click between us.

Fast forward 2 years he messages me out of the blue and we become quick friends, This was a rough time ln my life and he helped me through a lot.

We began dating long distance and he admitted to me he felt a strange connection to me straight away and wish he’d been able to steal me away back then. I’m his first love and I have no doubt about that, and that he loves me with all his heart, theirs something about the way he looks at me that makes me believe it.

He used to kinda be with the girl (we’ll call her Amie). Amie was very manipulative and unkind to him and they were never actually dating and didn’t have a sexual relationship, but he had feelings for her and was very hurt when she would threaten to leave. In the end he broke it off with her and blocked her. About a month before we got together she made a new Snapchat so she could re add him and they started talking again.

Our only issue is this girl. The first thing that happened was that I felt insecure he was still talking to her on Snapchat so I looked through his phone. In the chat was a photo of her butt and him saying she has a nice bum. This obviously blew up but he blocked her saying it hadn’t even gone through his head how wrong it was because he’d never actually had a girlfriend before.

The second event is very recent, once again I began to feel an odd nagging feeling of insecurity and went through his phone again. To find he had unblocked her and saved her under a male name so I didn’t know they were chatting.

When I confronted him about it I asked what was going on and he told me he’d unblocked her because she’d been messaging his sister wanting to hang out and we wanted to tell her to back off. And he didn’t want me to worry their was anything going on and that’s why he saved her under another name. He said the conversation had been short and he had reminded her he still had a partner. He has told me that theirs absolutely no feeling for her left or any attachment.

I’m very anxious about the whole thing though. I don’t want to end my relationship because we get along very well, he has gotten me to get to know his family and wholeheartedly wants me as a permanent part of his life.

What do you girls think? Is this forgivable?