orgasms and better sex

When my husband and I do have sex, it's not fun, for me.  I don't get any pleasure out of it and don't get to orgasm because he stops going when he cums.  It takes me a while and he doesn't hit the right spots.  Because I don't enjoy it, we rarely have it.  How can I get enjoyment out of sex and him to understand how to hit the right spots?