Long question involving a relationship between minor and adult?

okey so when i was 17 i was in a relationship with someone who was 19 but turned 20. my mother found out and made many threats but eventually got over it and this person continued to live with us as a roommate. this person also used my mothers computer to look up pornography and was called out on it and this person moved out. now im 18 and have been secretly meeting with person because we remained really good friends. i am forbidden by my mother to see this person. she states that she could take legal action and that legal action is under way involving the pornography found on her computer. she gave it to someone to look at and she says its out of her hands. this all took place about 2-3 months ago and nothing has happened. what can she actually do and what could actually be done, like as me getting in trouble? besides me possibly getting grounded since i live under her roof and making her angry, can anything legal happen? she never saw us kissing and has no proof that we had sex or even kissed since we just told her honestly that we were together after she found out by searching my phone and finding a text that said i love you. what could be done? im tired of not being able to hang out publicly with my friend because im afraid of what she could do. please help!