Ehh every guy is different.
See how it goes on the dates and you will be able to judge it better if it is appropriate to have sex.
Wait at least a few months and date him then get sexual.
If you know him on a personal level and you want to be in a relationship obviously, you've taken a liking to his personality and its not just the pics you've take a liking too.
I've know and liked this guy for about 10 years weve always had this unspoken sexual thing between us but in these 10 years weve never done anything maybe flirt and send pics and all i wanna do is fuck his brains out!! Just try to get in an actual relationship before you have sex with him, it makes sex like 100% better knowing its someone you love and someone you're in a relationship with, its not as special with just a guy you've sent pics to and stuff.
Though I don't really date really still I wouldn't leave her hanging unless we agreed to that from the beginning.
If we ever start talking in a i wanna date u kinda way should i wait to have sex with him or is knowing him for 10 years and flirting long enough lol I think its great you're looking for a relationship rather than a friends with benefits kind of thing! Also i'm kind of confused lol, your title says you want to fuck his brains out but yet you say you want a relationship so i'm not sure which one you want, maybe both lol? If he doesn't want to be in a relationship, its fine there's a lot of fish in the sea! I guess if you want something more than just a fling out of the relationship then you might want to go on a few dates before having sex.
You may know him for a long time, but you may not know what he is like as a sexual interest or dating or romantic partner.