6 months ago I moved in with my boyfriend of five years. It is great in most respects. I wouldn't ask him to give up his friends for me as I want him to be happy but at the same time there are alarm bells ringing in my head. If the relationship quality is high during the time you are with him, and if you trust him implicitly, then I'd say that his desire to be out with his friends is something you should work hard on granting him gracefully.
Relationships are dynamic things and especially so during the first few months of living together.
Every couple has to figure out how to take two different lives and integrate them into one shared life. Most of the time, this involves a negotiation amongst the partners with regard to how much separateness each will retain. And like any balancing act it will change over time. Talk openly about what your fears are with your boyfriend so that you can help each other come to an acceptable and comfortable balance. About five years ago, my then wife, informed me that she was a lesbian and filed for a divorce.