Dating! There is an old fashioned term. I never liked that term.
If you were interested in someone you just enjoy time with them and evolve.
The important term is when did you commit to only seeing that person for more significant long term reasons.
In my mind there are 5 important dates in a relationship.
1. When and how did you first meet
2. When did you each commit to the relationship
3. When did you decide to become married
4. When did you marry
5. When did you part
Number 2 for me is the most important one. 1 and 2 are the only necessary ingredients although we all know that the other ones can happen.
For the question: 3 years. Not married now.