He Thought I Cheated

So, I just started working somewhere new. And there is a really sleezy manager there, who is the same age as I am. Being the only manager that always had the same shifts as I did, I had to take his number in case of emergencies.

Now this guy was constantly hitting on me, trying to touch me, saying things that he would do to me.. all round being totally unprofessional and rude. I chose to ignore it, as I dont like working unharmoniously.

Until one day I was working late, and I had left my phone at home. I got home to a raging boyfriend. He told me to look at my inbox on my phone. Message recieved : "I wish your boyfriend wasnt there too. Especially when I think about all the orgasms I can give you."
At this point I would like to express that I have never, ever cheated on my boyfriend. I have never even thought about it. He's the love of my life.

So obviously he was pretty angry and automatically thought that this recieved message what a response to one that I had sent, or to something that I had sent. We managed to talk things through and all, but he still has a doubt in his mind.

What I am asking you now is that given that I have never done anything to break his trust before, and given that I have been nothing but loyal, and given that I had an answer for every question that he asked, shouldn't I be granted the benefit of the doubt just this once, and have a clean slate wiped?