Relationship Anxiety

I have been seeing this girl for a while, I really like her, we were getting along great & things were going so well. She then split with her boyfriend at the time, so we could be together. I’m pleased she did that as it makes things so much easier for us. We are really compatible & I love her so much. Recently I have developed this anxiety which after some Google searching I think can be narrowed down to a couple of things, I have a fear of intimacy & also a fear of sex. We have had sex loads of times before and never had a problem, but now I feel pressured into having sex. I have spoken with her about this and she understands that I’m struggling at the moment. There were a couple of instances were we were having sex but I couldn’t keep an erection, this plays on my mind too. I also feel like I’m constantly thinking about other things & what needs to be done, rather than focussing on being in the moment.
I don’t have an issue hanging out with her & I love her company, I love showing her affection, and I used to love sex. It’s just that now things are getting serious, I start to get worried. I want nothing more than to make it work with this girl as she’s very supportive & understanding.
I am quite a mature chap, but have only had one relationship & it took me a lot of years to lose my virginity. I might have a fear of relationships too which could all be intertwined.
I am unsure what to do? I don’t know who to speak to? Has anyone else had issues like this before?

Hello SB: I noticed this is your first post here on PC. So... welcome to Psych Central. The Men-Focused Support forum may also be of interest to you. Here's a link:

https://psychcentralforums.com/men-focused-support/

I think the only thing I could suggest, with regard to this, would be to seek the services of a mental health therapist who can work with you on your relationship anxiety issues. Here's a link to an article by our host Dr. John Grohol, Psy.D., from Psych Central's archives, on the subject of relationship anxiety plus links to 2 articles on attachment styles:

What is Commitment Phobia & Relationship Anxiety?

What Is Attachment and Why Is It Important?

What's My Attachment Style and Why Does It Matter? | Happily Imperfect

I hope you find PC to be of benefit.

Keep a open line of communication to Her. Let Her know what's going on so She knows.
Keep a clear mind when Your with Her. Focus on Her and enjoy the time Your together. Don't over think things.
With the erection problem I would suggest keeping Your head in the game to put it delicately. Enjoy what's happening and going on. Keep Your train of thought on what's going on, there, that moment and be positive.