Is my boyfriend cheating?

My boyfriend and I have been together for a year. I bought him a puppy for his birthday and moved in about a month ago. All seems good and didn’t feel like there was a reason not to trust him.

More often than not I’ve noticed a few females appearing more regularly commenting and liking his posts/ pictures but never when I’m tagged in them or have tagged him in them.

I’ve confronted him but he uses the excuse “they are just people I’ve known for ever, she’s my accountant, so I’m and so fourth.

Lastly things have seemed different as we used to have sex 4 times. Week and now it seems like 4 times a month. I’m not sure if it’s because we moved in together and we are just trying to adjust or it’s because there could be someone else.

Last night I asked him to run to to the corner store to pick up milk and cheese.The store is a 5 minutes away so I wasn’t expecting it to take long yet, it took him and hour before he showed back at home. I asked him what took so long and he claimed “he had a disagreement with the flu clerk and wanted someone else to cut the food.” Naturally I was hesitant to buy the excuse but didn’t feel like fighting.

Fast forward to today, he walked in the house, opened his phone to read the message I sent 3 hours ago and proceeds to say “I’m not sure why but my notifications for my phone are turned off so I just saw your message.” I asked why they were turned off and his answer was “I don’t know.”

I’m not one to snoop through people’s phone so I would really like someone else’s opinion as to if I’m just being overly sensitive or if this throws up some major red flags?