Has anyone else experienced this?

I've been dating my boyfriend for over 5 years now. I've never been so in love with someone in my entire life. But for the last year or so I've been struggling to have sex with him. Whenever we start to get heated I suddenly get a huge surge of anxiety and he cannot penetrate me. It's completely locked down. Not even fingers. We've tried multiple things to help me relax. Massage, complete quiet, music, TV, talking and being silly and then sexy time. Occasionally he can successfully get up in there but I'm usually uncomfortable and feel like I can't stop squeezing.