What do you think about people who marry their first boyfriend/girlfriend?

Just curious. My parents keep telling me I will have many more boyfriends and that I will/should date around. They use the analogy “It’s like eating one type of cake and saying it’s your favorite. How will you know that’s your favorite if you’ve never tasted anything else?”

I disagree though. My whole retort to that analogy is “Well what if it taste a bunch of other cakes and it turns out that the first cake I tasted really was the best one?”

I just don’t understand why I should be forced to date others if I really don’t want to. I’ve maintained a strong and loving relationship with my boyfriend for 3.5 years. We’ve talked about marriage and children and we have similar morals and values. If I love him and I’m happy, why should I leave him to go search for something I already have? He’s not perfect, but he’s still everything I truly need and want. Why should I give something up that some women spend their whole lives searching for? He’s my first boyfriend, but there is a reason for that. I’ve talked to guys and was always pretty clear as far as how I wanted my future husband to be. He might not be what I physically pictured, but he is more than what I could ask for in terms of everything else. I have talked to other guys, but I never thought any of them were actually worth dating. I always figured the point of dating was to find someone I can spend the rest of my life with. After all, why would I want to waste time being with someone that I can clearly tell I would not stay with them in the long run anyway? I don’t want to leave him only to find out I was right in the first place…..but I keep hearing everyone around me say it’s wrong to end up with my first boyfriend. I am content, but I feel like I am being pushed to search for that one guy that meets 100% of my requirements. But I feel like that doesn’t exist. Why should I give up my guaranteed 95% for a very risky and possibly non existent 100%? I’m sorry if I’m asking a lot or being repetitive, I just have a lot on my mind. I’m not unhappy in my relationship, so I just don’t see the point….