Friction and frustration taint your relationship, whether on a subtle or more overt level. Even if other aspects are more positive, this one adds some conflict to the mix. Although you're both comfortable as individuals outside the relationship, as a couple, you each face challenges to your individuality that can be difficult to deal with.
This is likely most apparent in your sexual connection -- your rhythms just aren't in sync. You end up wanting different things at different times, and moving at the same speed is difficult. This doesn't have to be a bad thing, but it does have to be communicated, both clearly and gently. The likelihood, however, is that you, especially, are the one who gets hurt; you perceive that your lover finds you lacking in the bedroom -- whether or not that's accurate. This problem doesn't necessarily center on your physical connection, however. It could have more to do with the ways in which each of you communicates. Trouble might arise when you see your lover as being crass, abrupt, inconsiderate, even rude. Arguments can erupt, and sometimes neither of you is able to distinguish important battles from insignificant ones. Each of you likely feels that you're not being heard: You must rely on your willpower to get you through these conflicts. A determined and combined effort to listen to and support one another will be key to keeping this going strong.