Any Idea's? Help?

Ok ladies I need some help. Advice.

So my boyfriend and I were out eating supper the other night and he told me that his Ex Gf, from 12 years ago, texted him "what's up?" Or Whatever. He said he answered the message, with "working and spending time with my girlfriend". But he wouldn't show me the texts and he said he deleted them. Blah blah.

Well, I then politely asked him to text her right then and to say leave him alone. He would not do it. The fuck. This scares me.

He says it was "nothing" and he dated her 12 years ago when he was 24-25. And he said how his Mom hated her anyway.

And we are TTC. Just started. I love him so much but this is raising an eyebrow for me.

Please help me.