How do i cope on this... My husband's p*nis is too...

Dear EEB Readers,

 I dont know how to express this but I need someone to help me out here. I have been dating a man for 3 years and he proposed to me on April 1st. At first I thought he was playing April fool prank on me until I saw the ring in my wallet.
I was so shocked and worried. I was worried because I found my mouth moving and saying yes without thinking. This man is very nice and caring. He may even be the only man who ever really cared for me but the big problem here is the sex. The sex is very bad. Infact it's so bad that I had to buy a vibrator to please myself. I have never reached climax with him in the whole 3 years we have been together. I have never told him this because I don't want to bruise his ego because he is very sensitive. The sex has never lasted more than 7mins and please don't ask me how I got to know the exact time it's over. I have always had to fake orgasm with him. And the unfortunate thing is the way he sweats when he is done like as if he just ran a marathon. So I am forced to compliment him and also fake being out of breath. The size of his p**** is not impressive.Please EEB Readers I have managed to cope all these years but I can't see myself marrying a man that can't satisfy me sexually because that would make me cheat on him. Please EEB readers advice me. Do I marry him like that and keep my vibrator close or do I walk away before it gets too late. Thank you in advance for posting this.