Here you are in your first really serious relationship. You’ve had a great time. You have been out of college for awhile, worked on your career and have a lot of great friends. You actually feel like an adult.

Now you’re about to make one of the biggest decisions of your life. You’re in love with a fantastic woman. You think she’s the one.

You want her to move in, but you’ve heard stories from so many other people about how everything changes once you move in with someone. The truth is that this is one of the most fascinating times of your life.

I remember when I first lived with somebody. I was 23 or 24 years old, and it didn’t last longer than two weeks. At that time, I really wanted to just move in with someone. I wanted to be an adult. I wanted to say that I lived with my girlfriend.

It was no longer enough for me just to have the relationship or to have sleepovers. I wanted to live with my girlfriend. I wanted to experience that. Unfortunately it didn’t work out.

Since then, I have lived with quite a number of women. I can tell you that living with someone makes the relationship take on a whole different dynamic.

You’re no longer playing sleepover games, or having those great 11:00pm phone conversations that end with you going over there late at night for incredible sex. You’re now part of their life every single day. Every day.

You wake up next to them, you have dinner with them, you share the refrigerator with them, you go to sleep with them, you learn their habits, and you learn what TV shows they like to watch. It’s not like spending the weekend together or spending the night at someone’s house three nights a week.

You are with them all the time. Their friends are in your house. Their phone calls are in your house. Their television shows are in your house.

You no longer can have that great signed football picture of you and Peyton Manning that was taken during the Indianapolis Colts’ training camp as the centerpiece of your living room decor. You are now going to become a highly domesticated man.

When you are living with someone, rules change. Sex will change. It’s not going to be as exciting as it once was.

It’s very hard to recapture those first six months of a relationship (when you’re not living together) once you are living together. You’re going to have to learn to make efforts with each other, and to be more aware of each other’s feelings, emotions, needs and desires.

You need to know when the other needs space or needs alone time. You have to understand each other’s moods.

You also have to “report in” when you live together. If you’re not going to be home until late one night, you’ve got to tell that person. You are not longer living alone, and you have to realize that you now have someone who will worry about you so you have to keep them posted.

You are now in adulthood. You are now living and breathing and wanting to be with that person every single day. You are in that adult relationship, and this is one of the biggest parts of adult adolescence.

This whole dynamic of what you thought relationships were is going to change right before your eyes. You’re going to have to become a person who not only thinks of themselves, but who thinks about somebody else (and sometimes thinks of someone else before you think of yourself).

There will be a lot of change from when you were living separately. You’re going to have women come over to your house for “girls nights.” You’re going to come home and have to listen to a bunch of women talking about things you have no desire to hear.

So what you need to do is to develop your own personal “man cave.” This is something I have determined is absolutely necessary if you are going to move in with a woman. Make sure your house is big enough so that you can have a man cave to go to when you need to just be yourself (and need to be by yourself).

You need to have a place you can watch football, read ESPN on the Internet, and talk to your friends on the phone. You need to have a place you can decorate any way you want. You need to have personal space in order to make a relationship work.

Moving in together is a big step. Moving in together is exciting. Moving in together is a part of your future. What you need to realize, though, is that moving in also means that you need to know how to coexist .

You need to understand that this woman you know now is going to change in a lot of different ways. When you are comfortable with each other, you change.

You need to realize that romance is not going to be something you not only have to think about, but you might even have to (gasp!) have to take a day or two a week and plan it. When you live together, you tend to take people for granted. So remember all the amazing things that you had together when you were courting each other — remember all the great sex and the spontaneity.

If you can remember all that — and keep that when you’re living with them — then the relationship has a great chance of success. Give each other space, make sure there is enough romance, and make sure that you continue to develop the friendship. When you do fight, make sure you have a space to which you can go back. Welcome to a real, good, fun and challenging time of your life.