Too tense for sex

When I had sex with my ex it would hurt a lot and I would be praying for it to be over soon, the first time was 2 years ago and the most recent was about 6 months ago that we tried and the last couple of times it wouldn’t go in at all

I’m going to a guys house this weekend that I’ve been a few dates with and worried if it leads to sex that the same thing will happen and I’ll just be extremely embarrassed

I’ve tried relaxing as much as possible and it still hurts, it’s as if it’s hit a brick wall and now I don’t know what to do

Please help x