I have been in a similar situation before. I discovered that I developed feelings for a close friend of mine, not because of the pressure of my situation, but because I am polyamorous.

The feelings I developed were essentially platonic and certainly less than a crush, but the reality is that my intimacy with my friend betrayed the boundaries of my relationship. This is a form of emotional cheating, and it is terribly hurtful to your partner, even if you feel blindsided by your feelings.

The best thing to do is confess to your partner and give them the honesty that they deserve. I lost my relationship with my partner, and I live with much guilt about my ignorance and immaturity. But now I understand the nature of my emotional connections to others, and I am able to explore relationships that fit my needs without hurting those I care about.