Questions regarding sexual doctrines

Is Masturbation (with porn) a sin?

Is Masturbation (without porn) a sin?

Is Divorce a sin?

Is having a girlfriend a sin?

Is having a non-christian girlfriend a sin?

Is F dominating a M in bed (wedded spouse) a sin?

If you do these and they are a sin, do you need to go to confession? If so, how often?

If you do these sins without being baptised, are they cleansed after being baptised?

If you are not baptised, do you need to care if it's a sin or not?

If you do these sins, die without baptism but accept Jesus in your heart, will you go to hell?

If masturbation is a sin, and you are not married, what are you supposed to do? In biblical times and Middle Ages (actually I think until late 1800s) people got married in 13-15. Masturbation wasn't needed since you got married early. It's of course wrong to have sex below that age, so it makes sense fornication is prohibited. But now, only 4% are virgins in their wedding day. Now, average marriage age is 28. Only sensible way to wait that long without fornication is masturbation.