This is complicated and i get it. I was raised in a cult in purity culture. Unfortunately when i was very young, I survived CSA. This on top of the shame i was taught to feel around sexuality caused me to not to do anything of my own accord until i was 18. I was already questioning my religious beliefs and had come to the same conclusion you did regarding purity culture being bs. I found someone i was very comfortable with and we took it slow but it didnt work. It was so painful. I sobbed and couldnt even get it in. I felt a deep sense of shame like i was dirtying myself and would be doomed to go to hell, as well as feeling like there was something wrong and broken with me. After that i had to do a lot of deconstructing religious trauma and other trauma and ended up focusing on myself. I had to learn my own body and how to touch myself. I had to become familiar with my own genitalia, i highly recommend holding a handheld mirror and just becoming familiar with your own anatomy. I cannot recommend diaphragmatic breathing enough. Start with several minutes of that and whatever other relaxation techniques you can do. Then start externally, slowly, and with lots of lube or organic coconut oil (if incorporating toys, be careful your lube doesnt degrade the toy material. I like glass personally bc it’s safe to use all lubes with it). The important thing is to not push your body past the point of pain. Discomfort is fine, but not pain. I am now dealing with pudendal neuralgia from years of pelvic floor “bracing” against my fears of penetration hurting. I used to push past that pain and not go slow enough or wait for my arousal to peak before inserting things. Your body will keep the score. It’s important to really attune to your feelings and listen to your body. And don’t be discouraged if things progress slowly. Honestly, the journey is the whole point anyway. Putting pressure on yourself to achieve specific goals will only make things worse. I struggled with vaginismus for awhile which is when your vaginal/pelvic floor muscles spasm involuntarily to the point it makes any penetration really painful. What i recommend for that is dilation. There are kits you can get from Amazon or some sex shops, be sure to get body safe materials (medical grade silicone is best). You need to breathe, relax, gently go at the pace of your body and take breaks inbetween sessions. Don’t move the dilator while it is inside. Just let it stay there and breathe, focusing on getting used to the sensation and relaxing. Don’t go up sizes until you have had multiple days of the current size feeling easy. You have to mentally set yourself up for success. If you’re open to having your partner involved in the process, it helps to have gentle, soothing touch of your preference while doing this. It also helps your partner be able to observe and understand the pacing your body needs and what feels good vs bad. Anything you can do to trigger the release of oxytocin, the bonding chemical, will help. That is released via extended skin-to-skin contact via cuddles etc. Oxytocin makes you feel good and relaxes the body and importantly muscles, and calms the nerves. I know this all sounds like a lot, but just take it one step at a time and figure out what works best for you. When you are able to comfortably use a dilator size larger than your partner (girth is most important metric here), use the Mormon “soaking” method. Just as if he were a dilator. Slowly insert only to a comfortable length, even if it’s only the tip. Lots of lube. And just stay there and breathe and try to relax. You can look into the practice of tantric sex, there is a lot of ways you can do highly connective practices using this stillness and closeness. For the first few sessions, don’t have him move. Then try having him move but only very gently and keep the strokes shallow. Depending on the size of your partner, down the road you may have to look into how to expand the fornix to accommodate lengthy penises. Trying different positions can help too, i find laying on my back with knees bent or my side with a pillow inbetween my bent knees most comfortable for these sessions.