It is very interesting to me that your previous relationships both ended at the 5 year mark. Did you know that scientists have isolated a hormone that cause men and women to be attracted to each other that fades round about the 5 year mark, sometimes earlier? If you are waiting for the perfect "attraction" physically for a relationship to work, you'll never find it. For a relationship to work you should be finding other things that will last and someone who is as willing as you to invest in the relationship.
There is no such thing as a "perfect" relationship or "perfect" guy. Trust your instinct about who you date. You've been dating long enough you should be able to recognize what you like and who you can trust. Don't wait for things to be perfect before you'll allow yourself to love someone fully. And don't keep waiting to make the "right" choice. there is no such thing as the "right" or "perfect" choice when it comes to who you love. When you do finally choose, choose someone who you like, love, respect, and with whom you are happy--someone you like spending time with--someone who shares similar values as you. You can't expect anything but that after 5 years "things change". Things always change. Just make sure you're with someone you don't mind changing with. Good luck to you.
Got married to my husband after knowing him for 2 months. Just had our 4 year anniversary and we're still doing great.