DD very emotional - is divorce to blame?

[semirurallife]

My DD is 6, and I split from her dad before she was 1 because he wouldn't be stop arguing (that was the nature of our relationship overall). But for some time things have amicable, she sees him regularly, likes his girlfriend, likes my new DH who I met before she was 2, and she's dealt well with arrival of little brother (now nearly 2) - but somehow she is very emotional and clearly doesn't feel secure. What can I do? Do i take her to a counsellor? What messages can I giver her to make her feel more 'whole' is that the problem? Any advice very welcome..

everything ok at school, friendships and so on as far as you are aware?

she has grown up with this arrangement so seems odd it would be having a negative impact now

yes, everything elsewhere fine, really sociable ... She is generally emotional anyway - she does get that from me to a certain extent, and she is going away with him soon which could be worrying her, but every time we talk about that she seems excited, and says, quite convincingly that she's NOT worried about that. Just wonder if she feels liker life is too divided or something...her best friend's dad lives in Dubai so she doesn;t think herself weird either..

she might just be wired that way? was curious as to why your first thought was the divorce though