Try using a water-based or silicone-based lubricant to make sex more comfortable and pleasurable and to reduce the risk of tearing. You might also try sex positions that give you more control so that you can make sure the sex that you do have is gentle in terms of impact and the way that it feels.
My boyfriend and I were having sex and we noticed there was blood everywhere all of the sudden. I found a cut on the outside of my vagina and the cut is pretty long and deep. What should I do? Can I let it heal on its own?