Grass is always greener on the other side.
Until you find they spray painted that shit

Honestly I think a lot of it depends on your age and maturity level. I loved being single in my 20's and even early 30's but you get to a point where you want something a little more solid. Someone you can trust to have your back, know will be home when you have a shit day and all the other stuff that comes with a relationship.
I knew I wanted to be a dad. I knew that I didn't want to be a baby daddy so, I found a woman that compliments my life (not complicates) and I hers and had babies. We were also old enough to not fall into a relationship that was founded on bullshit or other factors that doom immature couples like religious / spiritual choices, money handling, kid rearing style, career and retirement goals etc... Sure, being a guy I get my share of porn in (of which my wife doesn't care) and sure I've thought about what it'd be like to get some strange but honestly, I love my life. My wife is fucking awesome (sex anytime I want and we literally are like horny teenagers, we take rides on my bikes, she even drinks beer and plays video golf

) and my kids...they fucking crack me up everyday. I wouldn't dare ruin any of that for some side pussy.
If different pussy is your sole reason for not wanting to fall in love with someone and committing to a loving relationship, you need professional help...or to grow the fuck up. With time, looks fade and then what will you do when you can't just go pick up some pussy? Die a pathetic lonely life or be forced to settle for some hag or abusive nurse to take care of your old ass.
A loving committed relationship is a long term investment in happiness as you grow old.
PS - I have buddy that got divorced 5yrs ago, got in really good shape and now he is the 43 yr old dude hitting on 20yr olds at the club since 30yrs olds already have "too much mileage" or are "psycho". Sure, once in awhile he'll get a dumb fish on the line but they never want to stay and be seen with an old ass guy. He's a cool guy but honestly watching him and listening to his "stories" comes across as really pathetic. He doesn't seem to be in reality as far as his age, looks, pick up abilities etc..