I normally wouldn't interfere in a mates personal life, but I feel like I just have to say something. If a friend hooks up with someone that is wrong for him then I'm unlikely to say anything. He'll find out sooner or later that she's just not right for him, but in your case mate, you told me things weren't smooth and that the past few months had been rocky, so when you told me that you were having a heart to heart with her on Friday, I'd assumed you were going to separate. I wasn't really supportive of you breaking up as it seemed as though you had a good thing going and that it was your usual "she wants to marry, but I don't so I'll dump her" phase. I didn't expect to see her at the BBQ on Sunday, but there she was. Obviously the heart to heart worked out and you were going to continue on.
Well, after spending the afternoon with you both, I've come to the conclusion that you stuffed up. Mate, you can do better. I didn't like her attitude towards you or your daughter, she was negative and gave you a hard time when you should have been enjoying the occasion. There was no excuse for being so rude, especially on front of people she hardly knew. As I said, I normally don't get involved, but you've had more than a year together and while you've said in the recent past that things aren't as they were, Mate, it's time to make the break. I know you are going overseas, enjoy your time away (might be a little cramped with your daughter in tow) but I know you'll have a ball, don't think about what you've left behind. Look to the future, it'll be great.
Mate, if you are reading this, act now, you know you need to.
All the best,