You could try this but you will have to channel your inner perv a bit.

You sound like a lion who has been beat up by the pride alpha and you are triggered when you try to bed his lioness.

In other words your limbic system is on self-protect mode rather than breeding mode.

Try this.

The two of you get comfortable. You gently play with her kitten, while she touches your goldfish.

Be close enough to feel each others breath.

Have her begin to tell how those two weeks transpired. How she felt, what he did, what she did.

When you get aroused, let her finish you and move on to something else. Done for that day. If you are up to it put her kitten through the gauntlet.

Next time pick up where you left off.

You want to make her experience a shared experience.

Your imagination is filling in the blanks and making you feel defeated.

Eventually make it a turn on for both of you. Figure it out.

Again, no secrets, shared experience, tryst and communication.

You can come back from this. Good luck!