My hubby was reluctant but I eventually wore him down and now he sucks cock with the best of them. So keep at it. Tell him that it's ok. And that there is nothing wimpy or not manly about it. Plus tell him to think of it this way. One is if he licks you after getting fucked and kisses you after you just got done sucking a nice boner than he has already had another man's penis in his mouth. So he might as well enjoy doing it and just going for it.