Becks I'm mostly the same - dh can 'finish' in other positions but mostly it seems to be that he lies on his back and I just sort of... hover...

and try to keep myself stimulated as obviously with him manually stimulating himself he gets dry, so if I were dry too...well re-insertion would just not work!... he would DIE if he knew I was posting about this!!! As for my boys, we conceived our eldest after 4 cycles, our 2nd eldest after 2 cycles and our 3rd pregnancy (which ended in m/c in March) on our first cycle ttc. SO, don't be deterred by the issue, other than that you really do need to be aware of ovulation and make that extra effort!!! as long as he's had his sperm count checked and that's alright, I'm sure it will be fine!!
Also I don't know much about home insemination but like Becky suggested, perhaps that is an option if there are more 'misses' than 'hits'... anything is worth a try right! Maybe you could do some googling or keep asking questions on JM about how best to do it.

and good luck and I'll keep checking in here, or PM me if you've got any other questions - I'm happy to help if I can!
PS. It's not all smooth sailing for us either - the other night he wasn't sure if he actually did ejaculate..like he said the feeling was like he would have but he just wasn't sure.. it is hard when you lose momentum between him saying yes and trying to re-insert quickly...!!! I am laughing now but just because I'm thinking about all the other people who might read this... but if it helps you then that's all that counts!!