How to deal with strict parents in a LDR? (long read fyi but would appreciate some help~)

My bf and I have been long distance from the start, and together for almost a year now. He's graduating this month from college, while I will be a senior next year. We are in a very loving relationship despite the distance and completely trust one another (knew each other since high school and although I didn't know him too well then, I knew he was a goofy, bright person) However I've had a lot of stress dealing with my parents when it comes to our relationship and it has really strained my relationship with them. It is mainly because whenever my bf or I visit each other we stay at each other's place for a few nights since it's just not possible to visit each other within a day (around 5-6 hrs apart by train). Just to clarify, neither of us stay with our parents currently since we attend college outside of our hometown. I didn't tell my parents at first so when I had told them I had gone to visit him for a couple days they were extremely upset and disappointed with me. They felt betrayed and lied to when all I had done was not tell them until after the fact. I didn't tell them prior mainly because I was terrified of what they would say and I knew they wouldn't have approved. They are the typical strict Asian parents and are also very religious so I knew the current conditions of my relationship just wouldn't be pleasing to their standards. After the whole fiasco of "betrayal" I promised to them from then on I would let them know if he or I would visit each other. However each time I've told them my mom would make sure to let me know how much my dad is suffering from working all day and basically try to make me feel guilty. My dad is paying for my college tuition and I am of course grateful but the fact that they try to use this reason against my relationship..? Because of all the stress I give them whenever we visit one another, I broke my promise with them last month and didn't tell them that my bf had visited. I felt so guilty and anxious the whole time, but it also felt right to just let my parents be happy by not knowing. I am 21 and I believe at my age I should have the power to make my own decisions of my relationship regardless of my parents opinions. I love and appreciate my parents but I have a hard time feeling this way towards them when they clearly aren't pleased or supportive of what makes me happy. Any advice or words of encouragement would be appreciated and thank you so much if you read through this all. ❤