I have been married for 21 years, together for 25. We met young (I was 17) and married young (I was 21). Kids came on the scene by the time I was 25. I can tell you that all marriages hit rough patches but with open, honest communication about wants and needs, lots of listening with your heart and compromise, you do survive them.
Young children are very energy sucking, particularly for one's sex drive. I know that there were many years that, while I enjoyed sex for my husband's sake, it wasn't really for me. But, as the kids got older and less labor intensive (or, at least, a different type of labor intensive), the drive came back (usually with more regular sleep). Having my husband help more around the house helped a lot, too. The open, honest discussions on this topic were painful, but I'm glad we had them. It made it much easier to have the open, honest discussions when the positions were reversed and my sex drive was through the roof and he was dealing with ED issues.
Happily, issues on both sides resolved nicely, without either of us resorting to inappropriate solutions, like affairs.
If it's at all possible, try to schedule regular times to be intimate (sex, cuddling, kissing, whatever works for you two as a couple). For my husband and I, during young children years, Saturday nights were the nights we put the boys to bed early and had a candle light supper and special time just for us. It could be just mac and cheese or pizza, but it was just us. Calendaring intimacy was really the only way we could make it happen for years. Fast forward 10+ years and the boys are now teens (17 and 13). It's so much easier to spend an evening out. The boys love their "bachelor" night to eat pizza and watch tv and we love our Tuesday nights out.
Another idea is to find a hobby to do together. For me and my husband, we've done everything from Harley Owner's Group to playing in a concert band together to taking martial arts classes together. Right now, my husband is taking college classes and I go with him. I sit in the student lounge and grade papers. After class, we have dinner and discuss what he learned. Hobbies like this keep the two of you connected outside the bedroom and beyond the kids. If you're planning on a lifetime commitment, remember...there is life after children!
Last but not least, I would respectfully refer you to these two great "experts." Check out David Cunnigham's website www.makingherhappy.com. Read past the sales pitch and subscribe to his daily e-letter. Better yet, buy his book and read it together. This has done more to enliven my marriage than almost anything else. Also, more for you, subscribe to Dr. Laura Berman's "Passion Files" e-letter. This is chock full of great ideas for women in the "sex/bedroom/romance" area. Again, I've gotten lots of great ideas that have improved my marriage from this.
Our 21st anniversary was only two weeks ago and I love my husband more now than I ever have. Yes, we're older, we're frumpy married people, but we still hold hands, steal kisses and fondles and jealously guard our time together like we did at the beginning of our relationship. Our sons just sigh, shake their heads and remind us that children are present and to please just get a room. We laugh and tell them they're lucky to have us as an example of the good, the bad and the ugly of marriage. Too few do.
I'm sorry this was so long. Good luck to you!