Especially for men, there's an emotional bond developed due to oxytocin release during sex. It's the "cuddle" hormone.

https://www.psychologytoday.com/basics/oxytocin

Men who have a dose of oxytocin tend to be less interested in anyone other than the woman they've bonded with. As time goes on though, they'll start to feel less of a bond. Now this can be helped with more intimate contact like cuddling, holding, kissing, etc as these actions likewise release oxytocin. So even if sex isn't on the table, more intimate contact will help keep a man from feeling alienated.

Since I've unfortunately been part of a sexless marriage this year, I can say from my experience that it's really easy to get "friend zoned" in a marriage. I kiss and hug my wife now just like she's one of my kids, it's no different. Seriously, she's become slightly more than a roommate. I can play video games and sports with my boys, do stuff and hang out with them. So they've actually got a one up on the woman I've been married to for 15 years.

Don't let it get that way. You need to work on strengthening the bond between your husband and yourself. Do things together that he can't get from his buddies, like cooking his favorite meal or watching a special show. Kiss him like you mean it, not just pucker up and smooch, but kiss like you did earlier in your marriage. Cuddle up to him at night or even just on the couch during the evening. The longer that you keep him at arm's length, the greater the chances will be that you'll reach out and he won't be there.