Proportionately by income. If A earns twice as much as B then the split is 67/33. If A earns 3x B then it’s 75/25.

Been there. It sucks. I’ve done it though - been the friend - but it wasn’t the same as before, especially when she started dating an idiot. Just be you, have a coffee and a chat but try to close up that open heart wound. Good luck.

I’d wait until after your undergraduate degree’s complete. No earlier.

Germany’s a decent enough country.

He’s calling your bluff. Call it back. Get boxes and when he asks what they’re for tell him that the moment he leaves for that trip you’re boxing all his shit up and sending it back to his mother’s where he can go when he gets back.

Your mom might be financially dependent on your Dad but divorce courts and lawyers can fix that.

Tell her

Unless you are going to agree to be bf/gf then you owe each other very little consideration.

Oh my good lord, NO

Nothing good will come out of that conversation. You do not need anything else to fixate on. Just accept that she's happy to be with you.

The problem is never the disparity in ages. People can love who they love.

The problem in 'age gap' relationships are two-fold: power imbalance and life stages

Example 1: 40yr old and an 18yr old. The 40 year old will usually hold more 'power' in the relationship due to more established career/finances but also due to experience. It's easier for a 40 yr old to lie to someone fresh out of childhood than someone who's had life experience. I don't think that this applies here since you are an established adult and in just a few years will have been an adult for longer than you were a child. Any 'power imbalance' in the relationship now is entirely due to personality rather than age. NOTE: while the power imbalance is a danger in all extended age gap relationships that does not mean that it is present in all of them.

Example 2: heterosexual relationships - F35/M55 or F40/M20 or F20/M50 The other issue is 'life stages'. if the woman is nearing the point where she really has to start trying to get pregnant if she wants to start a family then she can hit trouble with a partner who is older and does not want to be a 75yr old by the time his kid leaves home or on the other end a partner who doesn't want to be a dad at 20. Similarly if you're 20 and want to establish a career but your partner wants a child before he's 'too old' then your relationship might buckle under that strain. You're 20 and want to go to clubs and travel but they've done all that and want a quiet life. You and your partner aren't that far apart, you're past your nightclub years and if you're going to be childless then I can't see an issue.

Meh, you're 32 not 17.

And the gap's just 9 years. My stepmother is 12 years younger than my Dad and they've lasted decades.

And no one's taking sexual advantage of anyone.

And you're both in the range for adoption should you want to start a family.

I can't see any downside as long as you're in to each other.