Should I stop putting effort in a 7 year long situationship?

Hi! So I am actually 17 and my “friend” .When I put the friend in quotations I mean that we aren’t really friends.

So I have known this person for about 8 years now and I don’t know where we are going relationship wise. 

I need advice on if I should try to pursue a relationship due to the fact of him liking the same gender in the OTHER way and the opposite gender (me) the romantic way.

He told me he can’t control it (I was not trying to ask him to change, I myself am bi) and it has to be a male. 

I love him to absolutely death and I know he loves me it’s just at a lower level.

For example: I’ve noticed he doesn’t like/prefer to say I love you first, he ONLY say it when we are leaving to go to sleep, I tell him I love him sometimes randomly and he just responds with “thank you”.

But on the plus side, I know he does show his love for me and his certain ways like when we are on call with another friend and the other friend says something that has obviously hurt me. He stands up for me. 

He also keeps on that we go to a buffet and that we sit alone and that I just comfortable and eat with him.

He also was very lenient with my personality, which is quite loud and annoying at times.

He also does not mind my piercings which I know is an issue for some people. They won’t kiss their partners if they have oral piercings because they think it will interfere with kissing.

I just do not know where to go with the relationship because he has told me before that he would never cheat on me and if he had a thought about it, he would immediately come to me because I expressed the fact that I am OK with his sexuality and if he were to discover someone he felt comfortable doing what I could not provide he should come to me and talk to me about it and he fully agreed with that.

An additional thing is that he and I always talk and expect marriage out of each other as if is an unspoken rule .

The same thing goes for living with each other (which I and he have no issue with) and having children.

I love him so much. I just don’t know if I should try to have a relationship with him because I don’t want to get my heart broken. I can see how differently he treats me over our male friends that he has known for the same time as me, but is quite an amount of years younger than us. 

Friend basically grew up with my friend is his father due to the younger friends father mainly being at work late and when the younger girlfriend’s father comes home, he is typically working yet again. 

So please help me find out what to do with him and the relationship because I would love for it to keep going. I just don’t know what to do and he is very sensitive about this topic and we are typically with the other friend uncalled to so I can’t really bring it up alone and private messaging , or just become frustrating for both of us.