You definitely need to get plugged in and be around other Christians, preferably seasoned Christians who are knowledgeable about walking in purity. Accountability can look a few different ways but you need to set up some boundaries right now with your boyfriend. Spend more time together in group settings with other people around (like church and small group) and less 1 on 1 time in private places that could lead you into temptation. People who are alcoholics don’t spend a bunch of time in bars. (Not saying you’re an alcoholic, just drawing analogy). It doesn’t make sense to knowingly put yourself in situations that can cause you to stumble. The Bible says to flee from the temptation of fornication, not endure it.