My partner is on Serequel and another anxiety drug during the day. We have had sex 3 times in about 3 months, he says the anxiety makes him not able to stay erect but I don't believe him, he won't even try to have sexual contact

- believe him. Desire can be present when there is no physical ability to "perform."

Have you spoken to his Physician? Have you researched Serequel and his other medication?

Medications can also take away desire.

Yes it sounds most possible, This can take away not only ability but desire.

My partner is on Serequel and another anxiety drug during the day. We have had sex 3 times in about 3 months, he says the anxiety makes him not able to stay erect but i don't believe him, he wont even try to have sexual contact

Both Judy and Fr_Chuck are correct.

Changes in sex drive and/or erectile dysfunction are both noted side effects of Seroquel (quetiapine). You can learn more about the drug here > Side effects (http://bipolar-disorder.emedtv.com/seroquel/seroquel-side-effects.html)