Your comments are telling, here.
It reads like you're not sure if you love him, but you've found a way of describing love that sounds like a lower threshold, and you're using that to justify saying you do. I did that in my early 20s, too. I really wanted to love the guy I was with. I thought I did. I didn't really realise I didn't until I met my now-husband... it's so much more than comfort.
It seems that you want to marry him because he comes with a ready-made circle of friends and family and that feels easier than building your own. It's low risk to you. It's a bit like an arranged marriage, in a sense... you're exchanging companionship and marriage for his circle of people.
To be honest, people do settle and some are happy to take a more transactional view. This might be how you want to do things, and that's okay, if it is. Unfair on him if he doesn't know, in my opinion, but fine if you're both aware and on board.
I'm glad I didn't. It wasn't easy to work on myself but I did it, and I now have a close circle of friends who are with me regardless, who love me for me, and who know me completely... and I have my husband's friends, too. I'll never have my own family, but I've dealt with my issues over that.
But more to the point, before I experienced it, I couldn't imagine a love like I have for my husband and he has for me. I've never been so naturally happy. He means the world to me.
I could be well off the mark here, but I recognise all of the things you're telling yourself to justify what you're doing.