Hey OP, glad to hear you have a nice LTR going! I’m 30M, so I haven’t reached the stage where too many of my people have kids.

I’m assuming she is your age or younger, so she really has little to no past before you. Which is good.

I’d say, first and foremost, that you should NEVER change your life plan for your LTR, especially when you are young. Every one of my guy friends who did that for their GFs ended up broken up within a year at most, but altered their life permanently. You are also too young to get too committed with anyone. You are only 22 and have your whole career/life/other women ahead of you.

What I find in general dating/fucking a particular woman, is that the longer you are with the same girl, the less fun it becomes over time, and the more work it becomes. Imagine you meet a girl who is 22, and you follow the timeline below, committing more at each stage because you enjoy being with her. All rough numbers.

First month, just started fucking her: casual sex with no major strings attached. You might have to take her on a date once a week too, but that actually might be fun! Maximum fun, with minimal duties. You are making off like a bandit here!

First 6-12 months, FWB phase: if she is pleasant enough, you start investing in her, spending time doing more than just fucking. Not every interaction ends in sexual, but hopefully you still enjoy her company. Still pretty minimum work for a lot of fun if you like her.

1 year in: she probably has demanded (and gotten) your commitment. At this point, you hopefully still fuck a lot and enjoy her company. But now there are rules. You can’t just go around fucking other women as much as you want. You need to know her birthday, get her stuff for Christmas, etc. You might need to hang out with her friends sometimes, even if you don’t like them. Same with family. At this point, it’s also likely sex with her is less spontaneous, and denial of sex may begin to happen. There is also more of an expectation to take her cool places for dates, and perhaps to pay for them. Still probably fun, as you are doing cool shit with her, but now you are putting in solid effort too. A fair balance.

3 years in: You are very committed, might even be living with each other. At this point, you are well out of the honeymoon phase. Without excellent game, sex has definitely gotten less frequent, and you might even be bored of fucking her. To make matters worse, she is now 3 years older, so less hot and perhaps she has gained some weight. She doesn’t need to keep up her appearance, as she already has you. You might also be living with her, and splitting bills, or paying most of them. You can’t just go out for a day to hang out with the boys, without telling her, so your freedom is reduced. The fun with her has become routine, and your duties and work are growing.

5-7 years in: you’ve gotten married or are about to. At this point she is definitely not as hot, you are almost for sure not having as much hot sex, and the obligations are growing. Now she will be expecting an expensive wedding, anniversaries, and maybe even kids, all of which you will have to pay for mostly. You probably aren’t going out with your boys anymore. It’s a lot of work to raise a family and make money. You probably aren’t having as much fun with her as you did before. That’s for both sex or doing cool shit together.

Years into the marriage: she is now definitely fatter and less hot. Very likely you have a dead bedroom. You have kid(s) now, so you can’t just leave. You need to pay for more stuff. Definitely no freedom, and definitely harder to game other chicks and bring them back to the house, since your wife lives there too. Now you have a lot of bills, a lot of work, and you can’t escape without fucking over your children.

End of marriage: divorce, half your shit gone, child support/alimony. You definitely aren’t fucking her anymore. Entirely obligations, no fun at all.

Your relationship might not have progressed exactly like this, but there is a general pattern. It’s that each stage of committing to a woman is nearly always less beneficial to you than the last stage.

The depressing conclusion to this is that in almost all cases, your best days with a particular woman have almost for sure already passed you by. The future for your relationship is nearly always less sex/fun and more work/bills. That’s why so many men (rationally) avoid commitment.

As for you OP, unless you are planning on having kids soon, I wouldn’t try too hard to keep your GF in your life. It’s been a good run, and almost for sure won’t get better. And note that this is NOT because she is a bad person or wants to get fat. It’s just the natural progression of a LTR.

This is a good question. People and their circumstances vary, as does the depth of their attachment and the number of their options. So it will be hard to put a figure on it.

In my experience not very long as someone I got together with to bang -as opposed to had something in common with to start. However I had a baby mother for about 8 years before I let her move in when a previous incumbent vacated. In that case, having a child together within 2 years of meeting was a tie that meant she wanted to keep me and so I could have sex with her when I liked at any point in those 8 years. I am not sure she would count as a plate.

One thing to consider is how long does infatuation last? 18 months to 2 years seems a commonly stated estimate by scientists. After that, I suggest that here is going to need to be clear benefit flowing to the female (as per Briffault) or at least anticipated long term benefit for the relationship to remain -it can't just be attraction and excitement alone that hold her. If she remains through the infatuation state, it is because she gains benefit. That may be she hopes to settle down with you, it could be that you are so high value she can't help but like to be associated with you or that you are convenient option to have in her back pocket when she wants some attention while seeing other guys/ between seeing other guys/ when she travels to your area and so on.

If you have a serious girl post infatuation, who has no one else, she is probably holding out hopes of a future with you and it may be kind to consider how much future she actually has.