<human>: I'm not sure what to do so why not ask some strangers. 3.5 year relationship going well. We have in the past almost broke up, and I almost left 4-5 months ago for another girl which so happens to be my best friend.

Current gf ask about engagement and marriage like any girl being in a long relationship. When I think about all of that I am very unclear if and when that would happen.

For whatever reason in the back of my head I keep thinking about the girl I almost left my gf for. We still talk, and I keep getting drawn back to her regardless what happens. We talk a lot and flirt etc.

Honestly I'm not sure what to do. I do know I need to figure this out soon though because it is not fair to either of them. I just kind of feel stuck and I do not like it at all.

Feel free to ask questions and try to help as you can.

Can you condense the text into three sentences or less?
<bot>: I'm not sure if I should stay with my gf or leave for another girl i've known for 3 years that I consider my best friend.