OP..
I don't want to disrespect you, but I really hope that you level up with the self esteem and get with someone who wants to be with you intimately as well as in general.
Based on what you have shared, your gf has no respect for you. She is also a control freak like any other person who uses sex as a bargaining chip.
IMO, there is NO woman on earth worth waiting for, if you aren't getting anything worth waiting for.
Also, what makes you think that marriage would get her to be intimate with you, should y'all take it to that level?
Of course do you, but one positive thing I can say about your situation is that you acknowledged that you agreed to be in a platonic relationship and that you have esteem issues. That is a start.
I do hope that you really have a serious gut check and cut your losses. But, you have to come to that conclusion when you are really to make a change in your life.
Lastly, I will share this and I am sure most men here would agree..
I will never enter an one sided, platonic "relationship"! If I ever decided to do it, then it will be on my terms, not hers! No kissing, no long hugs, and definitely no cuddling, spooning or anything that may cause arousal. Wanna play that game, then cool.
I would go super duper old school with it to the point where I may need a chapparone in order to be around her. I don't think any virgin or born again virgin would agree to it, so there would be no relationship.
Good luck to you though..It's your life to live after all...