1. Age can matter, but its a very individual thing (it doesn't matter to everyone). If you're very different ages then your life goals could be very different, I think it's important for you to have some conversations about where you're at in life (do you want kids, does he have kids, do you want to travel or settle down, etc?).
2. Trust your gut instincts, look out for red flag behaviours.
3. A guy who see's you as real respectable relationship material will be happy to introduce you to his friends and family after a little while.

Are you disinterested in what you're doing sexually, or is your libido low (or both)?

I wouldn't want the password to my partners social media, they're entitled to their privacy (and I trust them).

"Eye raping"- Umm, he's just looking at people. Straight guys are naturally attracted to nice bums & boobs. And when a hot guy walks into the room, you probably check him out too!

Being in a relationship doesn't mean that you become blind to the rest of the human race. You sound very insecure and oversensitive about this issue. Is your self-esteem Ok?