Hi Lil - There is a lot of emphasis on THE ONE now but - and please regard this as caring advice from someone older who has experienced more relationships - what funnygirl says is correct BUT you can feel that way about someone who is a total sh1t, feelings of first love are also feelings of sexual attraction and they can wear off. THE ONE is someone you can share the rest of your life with and, unromantic as it sounds, after the first flush of attraction wears off the rest of your life does usually include mundane day to day stuff and sometimes quite hard times. Bearing that in mind I would say you should always take of the rose coloured glasses and look at this person honestly. Is he kind to you, does he help/listen when you have problems, is he supportive of your ambitions, does he make you feel good about yourself, is he reliable, does he help around the house (really boring but can be a huge problem when you live with someone if they never help you practically) the list is endless, in short is he a friend as well as a lover, someone who you KNOW will stick by you through thick or thin. If you actually look at him in this light and think 'actually I don't 'like' you very much' then he may not be THE ONE. If he meets the criteria then he is!!
I say this as someone who thought she had met THE ONE when I was 17 and I gave up uni , travel and the offer of good job to stay near him because he wanted me near him. I thought that was wonderful and 'loving' until one day I realised that this man didn't really love me - if he did he would have encouraged me to accept these opportunities to better myself and grow as a person.
So hopefully your fella is THE ONE but my advice, take a really honest look at how you interact together before making up your mind.
PS I met and married my ONE after knowing him as a friend for 8 years, 25 years on I still love him to bits and there's no-one I'd rather have beside me when my back's