Do you consider this cheating?

My boyfriend was messaging his BROTHERS EX girlfriend who’s happily in a relationship and has a new born baby and he’s asking about her new baby and asking her to message him when she’s alone and not with her boyfriend. I just learned about these messages so this happened in April. It’s now basically December.

*** also I’m 30 weeks pregnant with his child.

UPDATE:

I thank you ladies for your input, I definitely used the wrong word when I said “cheating”, it was the first word to come to mind. but we’ve been together for 2 years and this is not the first time I’ve caught him messaging another female behind my back, and he deletes all the messages on his Facebook with females so I wouldn’t even know. I only know that bc when we are laying in bed or cuddled up I just so happen to look at his phone. And I don’t go through his phone either because I’m not a insecure 16 year old, I trust him. But it’s just like The other ones were his ex gf, even tho he knows I’m uncomfortable with that, And a girl he used to fuck talking about his “sex dreams” of her. but I just feel it’s wrong to go behind my back and message another female asking her to hit him up when her boyfriend isn’t around. It makes me wonder what he would of done if she had messaged him. It makes me feel worse about myself also since like I said I am 30 weeks pregnant and feel like a huge whale already and this kind of behavior just shits on my self esteem. I’ll bring it up to him but he has a “I don’t care “ attitude so we will see how it goes.

**Side note I’m NOT insecure about the conversation lol I don’t care if he messaged a female asking about her baby, he knows who she is as she was with his brother. It’s the fact that he asked her to message him when alone and not with her boyfriend.