Is it awkward to keep an ex as a friend?

It can be awkward of course. Some do keep former lovers as friends
but for most it's hasta la vista, baby. Depends where UR both at with your
true feeling for each other.

I am friends with most of my ex girlfriends and it has never been awkward for me. Sex gets brought up all the time with me and it never makes things weird. I kinda like talking about it.

If before being an ex, he was a good friend then guess having him be a friend again wouldn't be too concerning. At least you wouldn't have to worry about watching your back every time; he would be just too good a friend to do that ;-)

If the break-up was a little too harsh, then sex could be brought up as last resort to arguments.

. Other than that that with friends its never a drag. ;-)

Yes it can be awkward in the beginning. Over time you can have a decent relationship. It gets hard though when you are ready to date someone else. I know personally I've had problems with new boyfriends being uncomfortable with me being friends with ex's and visa versa. Sex will come up of course when trying to be friends with an ex because there is usually still that attraction there. Fooling around here and there happens, but isn't healthy if you are trying to just be friends. In the beginning, if you want to hang out as friends, do it in a group, to eliminate the temptation to hook up.

It can be a little awkward but if you are seeing them enough (in my case) I got over it.

If there is an awkward silence that's weird
but if there is a good conversation then it's good. It also depends on the person and how close you were to them and about the sex I'm a virgin and I plan to stay that way.

Depends on your attitude and how you act as his friend. One of my best friends is my ex, and I know many girls who have best friends who are exes. You just need to put all of the romanitc feelings aside and focus on your friendship. Of course if you guys were physical its going to be more awkward, but that's a given haha.

Yes, it is awkward, to some extent. There is always the thought that you were together at some point, that you have had sex with the person. Even if you were friends before, there is still a level of awkwardness there after you break up.

That really varies. Where you friends first? If so; and it was a good friendship that lasted a pretty long time, I would say "yes". Actually, by you even still asking "can I be friends with my ex", there is a really good shot that the answer is "yes". A lot of exes would never even dream of being friends!
However, I would advise that you guys not be alone for awhile. Sex happens and that will put you back at square one; it turns into an endless cycle of breaking up, hanging out as friends, having sex, being "back together", etc, etc.