Hi dear user. Welcome to HCM
I understand how this can worry you, and avoid you to enjoy your sexual relation.
I should know first if you have any organic condition. Which I don't know of course. But you can do some tests, to evaluate your actual health level. Like hemogram,
glucose test and
lipids levels. A blood pressure control could be useful to know about comorbidities like
hypertension.
If everything is normal, and you don't have any organic problem, such as, hypertension or
diabetes, then we can talk about psychological aspects.
The psychological part in a sexual relation, gets a lot of importance. When you say you can not concentrate about your partner, you should should ask yourself. .
What stuff are in your mind while while foreplay?
Why do these stuff appear?
Thinking Is related to her or to you?
If you have answers to these questions,and the problem is about your partner or even you, talk to her. Communication is really important and sometimes is the cause of many of these situations.
Is a confidence problem? What does make you feel uncomfortable, or non confident? Is it about your partner? What do you you think about? Identifying these and Talking to her, can be your help, and solution . Remember, your partner, can be wondering what's going on, too.
When you think about different stuff, non related to sex during your sexual activity, your libido goes down and it is normal sometimes. But when it is keeped a lot of time can cause troubles. If If you keep concentrating about stuff rather than sex probably you will have problems again. Try to talk to your partner, solve with communication, and then try again.
Don't think. Enjoy your sexual moment.
If you keep with troubles. You should see an specialist. Couple therapy if needed or psychology.
Hope Hope to be useful
Dr. Nieves