sagitta I'd be inclined to try to bf exclusively for say the first 8-10 weeks or so to get your supply properly established before you start introducing formula. If you start off mixed feeding then then you may find your supply never properly establishes (you might be fine some women are -- but on the whole introducing formula from the start makes it difficult to keep breastfeeding even partially).
DH is fine with my breastfeeding, I don't think he's too bothered about feeding the baby TBH (although I'll try expressing so after we've got my supply established he can have a go if he wants to). With DS we established that bathtime was DH's thing and special bonding time. Also he did virtually all the nappy changes if he was at home (that was my suggestion for special bonding time ).
MathairNua -- baby will get what he/she needs, it would be you who risked missing out (so vitamin supplements generally a good idea for breastfeeding mothers who aren't eating very healthily)... Sows who produce milk for formula only eat grass and I presume your diet is more varied than that...
I didn't feel anything that I knew was the baby with DS until 22/23 weeks last time (and plenty of my RL friends said the same) -- I was starting to feel paranoid with seemingly everyone online feeling things much earlier. This time I think I may be feeling flutters but I wouldn't stake anything much on it; could still just be wind.