Like with any relationship, you both seem to have needs and expectations. You mentionned before that you accepted his proposal, but postponed twice. Perhaps he feels a sense of doubt from you, or a lack of commitment. Unfortunately, he is probably not recognizing the level of commitment you have for him. I mean, you are literally fighting against your personal nature (being lesbian) and seriously considering giving up on sex with other women, and commiting yourself to a long term relationship with a man. It is not easy giving up and changing a core part of yourself, especially if you believe that you are born gay/bi/str8.

You definitely need time to consider, make a decision and adjust to that decision. And he HAS to give you that time. What you are doing and going through demonstrates to me that you are quite a catch. I don't think he would seriously want you to just jump into a marriage on a whim and get hitched without feeling confident in your decision. Otherwise, you would end up questioning yourself and your decision, and then he would sense this and do the same.

I do think about you and your situation. I wish it were as simple as my decision. I've known all my life I was bisexual (and it really is harder for men to be bi). I've always found it easier being with guys because they are simpler and their needs met easier. And sexually I prefer men. However, when I met my wife I knew she was the "one", and that I was willing to forego gay sex. Believe me, there isn't a day that goes by that I don't think about, fantasize about, or masturbate to gay sex, but I am commited to my wife.

I sincerely hope you can find the balance with your guy. You shouldn't feel rushed into a decision. Perhaps if he won't give you something as simple and as free as time, you should really think is he is the "one" for you.