I sincerely hope you won't take this step. God gave marriage to us, and one of the restrictions He placed on it is that sex outside of marriage is wrong in His eyes. He has never promised to bless any relationship that willingly violates His commands.
In addition, you need to think of others. In all likelihood, you both have nieces and nephews; what example would you setting for them by living together apart from marriage? Paul's advice to his pastor friend Titus could apply to you as well: "In everything set them an example by doing what is good" (Titus 2:7).
Instead, I urge you to seek God's will for your future. Your letter indicates that you have never thought about God very much–but isn't it time you did? Someday soon, you will face God to give an account of your life–but are you prepared for that day? Life is uncertain, and none of us knows how much longer we have to live–particularly as we grow older.
Don't live only for the immediate moment. Instead, commit your life to Christ, and make it your goal to live for Him. It may well be His will for you to remarry–but even if it isn't, He wants to fill your life with Himself. The Bible says, "The Lord bestows favor and honor; no good thing does he withhold from those whose walk is blameless" (Psalm 84:11).