Am I supposed to be ok with this

My husband of 14 years is a handyman. He gets jobs by word of mouth from past jobs and friends. Well, a friend referred him to this single woman that is same age as he is. (he is 8 yrs older than me.) She started out wanting a wall redone or something like that. It was a short job. He was at her house everyday for over a week. I thought he was finished with her but then he says she has more work for him. And he kept going to her house. I'm talking all day. One day his phone rang and a message was on the screen. It was from her....he was outside so I read it. The first message said ......hey babe, I miss you. I was thinking about you and your poem and the Yukon and you and Idaho. Ok....wtf. He recited her the poem he recited me when he and I first met. The yukon....not sure what that was....and Idaho...that's where he is from. Now......he has been going to her home almost every day, and she continues to call him pet names like, babe, sweetie and all with winking or heart emojis. I have told him I'm not comfortable with how she is talking to him. He said it's nothing to worry about. We'll it is. I don't think another woman should be talking to my husband that way. He refuses to stop going to her house and working on her house., it's just the 2 of them all day every day. I just found out that they went shopping for tritip dinner and they bbqd and he didn't work at all that day. He now deletes the calls and texts from her. One day he was at her house for 16 hours. Says he was working. Is it just me or am I right.....he is cheating on me.? What am I supposed to do? Oh....and for past jobs he has let me come along to help..but refuses to let me go to her house to help. Says it's because I'm jealous and would cause problems. HELP