Relationship going okay?

Two things really

I've been dating my boyfriend for about 3 and a half months, we spend every second of the summer together living at each others houses. I'm incredibly close to him and in love for the first time.
Recently though i haven't felt that excitement to be with him, and have been having slight doubts about the future because of that. I still love him, and he loves me, but i'm scared that i might be drifting away and its bringing all sorts of doubts.
Is this normal in a relationship? i've heard about the "honeymoon" phase of a relationship, is this just me reaching that?
I know it seems early, but we truly are like the same person, everyone has said so, and we get on really really well. we really did spend every minuet of the first 3 months of our relationship together, like literally every day. When he went on holiday for 10 days he nearly got an early plane home because of me, i actually had to talk him out of it.
the thing is now we have both started college, i see him about 3 or 4 days a week. We still message each other every day, but it seems like we're both much less passionate all of a sudden. we are talking about the future, like moving in together next summer when i start university. But all of a sudden i've had doubts, because sometimes things do go wrong, today was one of those days where it just wasn't that great in general. I don't get excited about seeing him anymore. I think i still love him but i don't get excited, is that normal?

My doubts about our relationship lasting very long term are mainly about whether he is "manly" enough for me if i'm honest.
I'm attracted to him and he's great in bed, sex isn't really an issue. The issue is more on me becoming the masculine one in our relationship sometimes it freaks me out. He has told me about his experiences with past relationships and he is bisexual. I have no problem with his sexuality, but in the past he has told me some of the sexual stuff he's done which really wasn't necessary for me to know. All of a sudden it has been getting to me, i've become paranoid, jealous and really insecure and doubtful. Now i've realised how him telling me these things has effected me, i've asked him not to mention the past anymore which he says is fine. I even get these feelings now when he at all mentions anything to do with his sexuality, which really is not something i can ask him to hide as it is part of him. I feel that now the only issue is me, and how i am now being stupid by letting random things freak me out about this relationship. How do i stop myself from feeling weirded out by his submissive side?
I love him way to much to end it, he's not that camp I'm very attracted to him.
Breaking up with him is out of the question really, i just don't know how to tackle these issues of my own.