I’m beginning to feel uncomfortable around couples and have avoided being around friends who are in relationships

I’ve been single for a very long time now and as time has gone on, so many of my friends have fallen in love and are either in loving relationships and/or married and I don’t seem to get bitten by the love bug at all whatsoever. Not only does it make me sad, but also makes me jealous of them and their abilities to find love so fast. It’s gotten to a point where it’s becoming uncomfortable being around them when you’re the virtually only single person they know at this point. It makes me feel like there’s something wrong with me because I was never able to fall in love with someone special. I hate that I have trouble being with these people, but at the same time I don’t feel like I belong because they have what I never will have.