I heard some rumors about his sexual interest which i couldn't believed in the first place.If UK laws strict towards LGBT at the time why would not he move to USA ? where LGBT has freedom to do anything as normal person except marriage at the time ?
USA has a far better social system on LGBT inclination than SL ?
he was married against his will by his parents from what ive heard. afaik his brother has officially said arthur c clarke was gay. even usa wasn't as tolerable as us in those times or alan turin could have easily escaped into usa.

we don't have enough evidence to evaluate his sexual orientation 

