Advice please?

Mary • Hi! I`m Mary. I have a BA in Psychology. Been dealing with PCOS for 22 years. I work at Sander’s Candy and Ice Cream Shop and trying to get my head around this COVID craziness!
There's a guy I really care for and I think he really cares for me. I believe in saving oneself for marriage, but I don't know if I'll be able to say no if one of us pushes boundaries ie making out while touching in naughty places. Clothes will go off and then you know what happens after that. How can I avoid the sexual tension getting to the point where inhibitions go out the window? Advice please?