Congrats junior, you have now become what we call "enlightened". That means you understand that every girl you meet is the same person with a different shape, haircolor, etc. It means you know that all of these bytches, even your own fukking mother belong to the game, so you should ruthlessly exploit them as much as humanly possible until you've gotten everything you need or they finally cant take it any more and tap out, before they can do it to you first. That means you cheat on them every opportunity you get, take their money if their stupid enough to let it get taken, try to fukk their friends if you can get away with it, purposely doing shyt they hate like cumming inside of them and then leaving them there to make them feel dirty, purposely not texting back after you give them the good dikk and they're in their feelings. Everything my nikka.
To answer your question about marriage and girlfriends, The only reason to marry a girl is to have children that aren't b*stards, and you leave them once they're past their prime. The only reason to have a girlfriend is if she pays all the bills and is easily manipulated. And in both instances you should be fukking as many women as possible whilst sending iloveu texts. Be a scumbag, they deserve it for what they will do to you if you get in your feelings over them.
Funnily enough, once you adopt this mindset opposed to the one where you're trying to do right by her and have a meaningful relationship and they start stunting, a complete reversal happens, THEY'RE the ones jumping through hoops to try to get you to settle down and do right by you, THEY'RE the ones that start getting possesive on some 'I dont want you goin out with ur friends anymore' or 'i dont want you going on instagram' etc. They start losing their minds over the fact that you truly don't give a fukk. Be careful though, emotional creatures as they are... this is the state where they are likely to pull out a knife on you or try to ruin your life in some way out of spite. Speaking from experience.